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This article presents the results of an adaptive design experiment in the recruitment of households and individuals for a two-stage national probability web or mail mixed-mode survey, the American Family Health Study (AFHS). In the screening stage, we based the adaptive design’s subgroup differentiation on Esri Tapestrysegmentation. We used tailored invitation materials for a subsample where a high proportion of the population was Hispanic and added a paper questionnaire to the initial mailing for a subsample with rural and older families. In the main-survey stage, the adaptive design targeted the households where a member other than the screening respondent was selected for the survey. The adaptations included emailing and/or texting, an additional prepaid incentive, and seeking screening respondents’ help to remind the selected individuals. The main research questions are (i) whether the adaptive design improved survey production outcomes and (ii) whether combining adaptive design and postsurvey weighting adjustments improved survey estimates compared to performing postsurvey adjustments alone. Unfortunately, the adaptive designs did not improve the survey production outcomes. We found that the weighted AFHS estimates closely resemble those of a benchmark national face-to-face survey, the National Survey of Family Growth, although the adaptive design did not additionally change survey estimates beyond the weighting adjustments. Nonetheless, our experiment yields useful insights about the implementation of adaptive design in a self-administered mail-recruit web or mail survey. We were able to identify subgroups with potentially lower response rates and distinctive characteristics, but it was challenging to develop effective protocol adaptations for these subgroups under the constraints of the two primary survey modes and the operational budget of the AFHS. In addition, for self-administered within-household selection, it was difficult to obtain contact information from, reach, and recruit selected household members that did not respond to the screening interview.

In push-to-web surveys that use postal mail to contact sampled cases, participation is contingent on the mail being opened and the survey invitations being delivered. The design of the mailings is crucial to the success of the survey. We address the question of how to design invitation mailings that can grab potential respondents’ attention and sway them to be interested in the survey in a short window of time. In the household screening stage of a national survey, the American Family Health Study, we experimentally tested three mailing design techniques for recruiting respondents: (1) a visible cash incentive in the initial mailing, (2) a second incentive for initial nonrespondents, and (3) use of Priority Mail in the nonresponse follow-up mailing. We evaluated the three techniques’ overall effects on response rates as well as how they differentially attracted respondents with different characteristics. We found that all three techniques were useful in increasing the screening response rates, but there was little evidence that they had differential effects on sample subgroups that could help to reduce nonresponse biases.

Responsive survey design (RSD) aims to increase the efficiency of survey data collection via live monitoring of paradata and the introduction of protocol changes when survey errors and increased costs seem imminent. Daily predictions of response propensity for all active sampled cases are among the most important quantities for live monitoring of data collection outcomes, making sound predictions of these propensities essential for the success of RSD. Because it relies on real-time updates of prior beliefs about key design quantities, such as predicted response propensities, RSD stands to benefit from Bayesian approaches. However, empirical evidence of the merits of these approaches is lacking in the literature, and the derivation of informative prior distributions is required for these approaches to be effective. In this paper, we evaluate the ability of two approaches to deriving prior distributions for the coefficients defining daily response propensity models to improve predictions of daily response propensity in a real data collection employing RSD. The first approach involves analyses of historical data from the same survey, and the second approach involves literature review. We find that Bayesian methods based on these two approaches result in higher-quality predictions of response propensity than more standard approaches ignoring prior information. This is especially true during the early-to-middle periods of data collection, when survey managers using RSD often consider interventions.

Survey researchers have carefully modified their data collection operations for various reasons, including the rising costs of data collection and the ongoing Coronavirus disease (COVID-19) pandemic, both of which have made in-person interviewing difficult. For large national surveys that require household (HH) screening to determine survey eligibility, cost-efficient screening methods that do not include in-person visits need additional evaluation and testing. A new study, known as the American Family Health Study (AFHS), recently initiated data collection with a national probability sample, using a sequential mixed-mode mail/web protocol for push-to-web US HH screening (targeting persons aged 18–49 years). To better understand optimal approaches for this type of national screening effort, we embedded two randomized experiments in the AFHS data collection. The first tested the use of bilingual respondent materials where mailed invitations to the screener were sent in both English and Spanish to 50 percent of addresses with a high predicted likelihood of having a Spanish speaker and 10 percent of all other addresses. We found that the bilingual approach did not increase the response rate of high-likelihood Spanish-speaking addresses, but consistent with prior work, it increased the proportion of eligible Hispanic respondents identified among completed screeners, especially among addresses predicted to have a high likelihood of having Spanish speakers. The second tested a form of nonresponse follow-up, where a subsample of active sampled HHs that had not yet responded to the screening invitations was sent a priority mailing with a $5 incentive, adding to the $2 incentive provided for all sampled HHs in the initial screening invitation. We found this approach to be quite valuable for increasing the screening survey response rate.

Large-scale, nationally representative surveys serve many vital functions, but these surveys can be long and burdensome for respondents. Cutting survey length can help to reduce respondent burden and may improve data quality but removing items from these surveys is not a trivial matter. We propose a method to empirically assess item importance and associated burden in national surveys and guide this decision-making process using different research products produced from such surveys. This method is demonstrated using the Survey of Doctorate Recipients (SDR), a biennial survey administered to individuals with a science, engineering, and health doctorate. We used three main sources of information on the SDR variables: a bibliography of documents using the SDR data as a measure of item use and importance, SDR data table download statistics from the Scientists and Engineers Statistical Data System as an additional measure of item use, and web timing paradata and break-off rates as a measure of burden. Putting this information together, we identified 35 unused items (17% of the survey) and found that the most burdensome items are highly important. We conclude with general recommendations for those hoping to employ similar methodologies in the future.

Large-scale, nationally representative surveys serve many vital functions, but these surveys can be long and burdensome for respondents. Cutting survey length can help to reduce respondent burden and may improve data quality but removing items from these surveys is not a trivial matter. We propose a method to empirically assess item importance and associated burden in national surveys and guide this decision-making process using different research products produced from such surveys. This method is demonstrated using the Survey of Doctorate Recipients (SDR), a biennial survey administered to individuals with a science, engineering, and health doctorate. We used three main sources of information on the SDR variables: a bibliography of documents using the SDR data as a measure of item use and importance, SDR data table download statistics from the Scientists and Engineers Statistical Data System as an additional measure of item use, and web timing paradata and break-off rates as a measure of burden. Putting this information together, we identified 35 unused items (17% of the survey) and found that the most burdensome items are highly important. We conclude with general recommendations for those hoping to employ similar methodologies in the future.

Survey costs are an understudied area. However, understanding survey costs is critical for making efficient decisions about cost-error trade-offs, as well as to accurately project future costs. In this article, we examine a measure of survey costs—per interview costs—over time in a repeated cross-sectional survey. We examine both measurement issues and variability in costs. The measurement issues relate to the classification of various costs into the appropriate time period. We explore several issues that make this process of classification difficult. A time series analysis is then utilized to examine the trends and seasonality in per interview costs. Under the assumptions of our model, after removing the trend and seasonality components, the remainder is variation in costs. This approach allows us to treat survey costestimates in a manner similar to any other survey estimate.

Survey costs are a major driver of survey design decisions and thought to be related to survey errors. Despite their importance, no common language exists for discussing survey costs, nor are there established criteria for identifying which cost metrics are useful for which purposes. Past efforts to study survey costs may have been hampered by the notion that more reporting is better reporting. This article starts by introducing a typology for survey cost metrics defined by the type of cost (estimated, observed in records, and actually incurred), currency versus non-currency measures, and level of aggregation (total, by components, per unit, relative). We also suggest a set of criteria – errors in costs, generalizability, and the degree to which a cost measure is informative about survey error sources – for evaluating the utility of cost metrics. We illustrate the evaluative criteria with the cost metrics. We argue that clearly articulating types of survey costs and resetting these baseline evaluative criteria for the utility of different types of costs will help us expand research in this critical area. We conclude with recommendations for future research in costs within and across organizations.

Telephone surveys have been a ubiquitous method of collecting survey data, but the environment for telephone surveys is changing. Many surveys are transitioning from telephone to self-administration or combinations of modes for both recruitment and survey administration. Survey organizations are conducting these transitions from telephone to mixed modes with only limited guidance from existing empirical literature and best practices. This article summarizes findings by an AAPOR Task Force on how these transitions have occurred for surveys and research organizations in general. We find that transitions from a telephone to a self-administered or mixed-mode survey are motivated by a desire to control costs, to maintain or improve data quality, or both. The most common mode to recruit respondents when transitioning is mail, but recent mixed-mode studies use only web or mail and web together as survey administration modes. Although early studies found that telephone response rates met or exceeded response rates to the self-administered or mixed modes, after about 2013, response rates to the self-administered or mixed modes tended to exceed those for the telephone mode, largely because of a decline in the telephone mode response rates. Transitioning offers opportunities related to improved frame coverage and geographic targeting, delivery of incentives, visual design of an instrument, and cost savings, but challenges exist related to selecting a respondent within a household, length of a questionnaire, differences across modes in use of computerization to facilitate skip patterns and other questionnaire design features, and lack of an interviewer for respondent motivation and clarification. Other challenges related to surveying youth, conducting surveys in multiple languages, collecting nonsurvey data such as biomeasures or consent to link to administrative data, and estimation with multiple modes are also prominent.

Responsive survey designs rely upon incoming data from the field data collection to optimize cost and quality tradeoffs. In order to make these decisions in real-time, survey managers rely upon monitoring tools that generate proxy indicators for cost and quality. There is a developing literature on proxy indicators for the risk of nonresponse bias. However, there is very little research on proxy indicators for costs and almost none aimed at predicting costs under alternative design strategies. Predictions of survey costs and proxy error indicators can be used to optimize survey designs in real time. Using data from the National Survey of Family Growth, we evaluate alternative modeling strategies aimed at predicting survey costs (specifically, interviewer hours). The models include multilevel regression (with random interviewer effects) and Bayesian Additive Regression Trees (BART).

Responsive survey designs rely upon incoming data from the field data collection to optimize cost and quality tradeoffs. In order to make these decisions in real-time, survey managers rely upon monitoring tools that generate proxy indicators for cost and quality. There is a developing literature on proxy indicators for the risk of nonresponse bias. However, there is very little research on proxy indicators for costs and almost none aimed at predicting costs under alternative design strategies. Predictions of survey costs and proxy error indicators can be used to optimize survey designs in real time. Using data from the National Survey of Family Growth, we evaluate alternative modeling strategies aimed at predicting survey costs (specifically, interviewer hours). The models include multilevel regression (with random interviewer effects) and Bayesian Additive Regression Trees (BART).

Introduction: Work meaning has gained attention as an important contributor to physician job engagement and well-being but little is known about how faculty participation in medical school learning communities might influence this phenomena. Our study goals were to determine how physician faculty members may derive meaning from serving as mentors for longitudinal learning communities of medical students, to understand how that meaning may impact other areas of their work, and relate our findings to existing literature and theoretical frameworks. Methods: The research team conducted, recorded, transcribed, and coded 25 semi-structured telephone interviews of faculty mentors from four US medical schools with curricular learning communities. The team used an iterative interview coding process to generate final themes and relate these themes to existing literature. Results: The authors identified five themes of meaning faculty derive from participation as learning community mentors: “I am a better professional,” “I am more connected,” “I am rejuvenated,” “I am contributing,” and “I am honored.” A sixth theme, “I am harmed,” encompassed the negative aspects of the learning community faculty experience. The authors found that their identified themes related closely to the theoretical framework for pathways to meaningful work proposed by Rosso et al. Discussion: The alignment of the themes we identified on the experience of learning community faculty to existing literature on work meaning corroborates the theoretical framework and deepens understanding of beneficial and harmful learning community effects on faculty. As learning communities become increasingly common within medical schools, this understanding may be important for leaders in academic medicine considering potential indirect benefits of this educational model.

This article presents results from an experimental study in Germany designed to test the effectiveness of a novel protocol for matching participants in a national panel survey with interviewers employing computer-assisted telephone interviewing (CATI) on selected sociodemographic features, including sex, age, and education. We specifically focus on the ability of the protocol to engender close matches between respondents and interviewers in terms of these features, using both theory and empirical evidence to suggest that this type of matching will improve cooperation rates in surveys employing CATI. We also focus on indicators of “success” at first contact (defined as a successful interview or establishment of an appointment for an interview) as a function of whether the matching protocol was in use on a given day and whether specific types of matches generated higher rates of success overall. We find strong evidence of the protocol effectively establishing close matches, and we also observe that matches based on education proved especially effective for rates of “success” in a panel survey that focused primarily on labor market topics. We conclude with thoughts on practical implementation of this approach in other settings and suggested directions for future work in this area.

Researchers are interested in the effectiveness of adaptive and responsive survey designs that monitor and respond to data using tailored or targeted interventions. These designs often require adherence to protocols, which can be difficult when surveys allow in-person interviewers flexibility in managing cases. This article describes examples of interviewer noncompliance and compliance in adaptive design experiments that occurred in two United States decennial census tests. The two studies tested adaptive procedures including having interviewers work prioritized cases and substitute face-to-face attempts with telephone calls. When to perform such procedures was communicated to interviewers via case management systems that necessitated twice-daily transmissions of data. We discuss reasons when noncompliance may occur and ways to improve compliance.

Researchers are interested in the effectiveness of adaptive and responsive survey designs that monitor and respond to data using tailored or targeted interventions. These designs often require adherence to protocols, which can be difficult when surveys allow in-person interviewers flexibility in managing cases. This article describes examples of interviewer noncompliance and compliance in adaptive design experiments that occurred in two United States decennial census tests. The two studies tested adaptive procedures including having interviewers work prioritized cases and substitute face-to-face attempts with telephone calls. When to perform such procedures was communicated to interviewers via case management systems that necessitated twice-daily transmissions of data. We discuss reasons when noncompliance may occur and ways to improve compliance.

Cyberattacks continue to evolve and adapt to state-of-the-art security mechanisms. Therefore, it is critical for security experts to routinely inspect audit logs to detect complex security breaches. However, if a system was compromised during a cyberattack, the validity of the audit logs themselves cannot necessarily be trusted. Specifically, for a database management system (DBMS), an attacker with elevated privileges may temporarily disable the audit logs, bypassing logging altogether along with any tamper-proof logging mechanisms. Thus, security experts need techniques to validate logs independent of a potentially compromised system to detect security breaches.

In this article, we investigate the relationship between interviewer travel behavior and field outcomes, such as contact rates, response rates, and contact attempts in two studies, the National Survey of Family Growth and the Health and Retirement Study. Using call record paradata that have been aggregated to interviewer-day levels, we examine two important cost drivers as measures of interviewer travel behavior: the distance that interviewers travel to segments and the number of segments visited on an interviewer-day. We explore several predictors of these measures of travel - the geographic size of the sampled areas, measures of urbanicity, and other sample and interviewer characteristics. We also explore the relationship between travel and field outcomes, such as the number of contact attempts made and response rates.We find that the number of segments that are visited on each interviewer-day has a strong association with field outcomes, but the number of miles travelled does not. These findings suggest that survey organizations should routinely monitor the number of segments that interviewers visit, and that more direct measurement of interviewer travel behavior is needed.

In this article, we investigate the relationship between interviewer travel behavior and field outcomes, such as contact rates, response rates, and contact attempts in two studies, the National Survey of Family Growth and the Health and Retirement Study. Using call record paradata that have been aggregated to interviewer-day levels, we examine two important cost drivers as measures of interviewer travel behavior: the distance that interviewers travel to segments and the number of segments visited on an interviewer-day. We explore several predictors of these measures of travel - the geographic size of the sampled areas, measures of urbanicity, and other sample and interviewer characteristics. We also explore the relationship between travel and field outcomes, such as the number of contact attempts made and response rates.We find that the number of segments that are visited on each interviewer-day has a strong association with field outcomes, but the number of miles travelled does not. These findings suggest that survey organizations should routinely monitor the number of segments that interviewers visit, and that more direct measurement of interviewer travel behavior is needed.

Nonresponse rates have been growing over time leading to concerns about survey data quality. Adaptive designs seek to allocate scarce resources by targeting specific subsets of sampled units for additional effort or a different recruitment protocol. In order to be effective in reducing nonresponse, the identified subsets of the sample need two key features: 1) their probabilities of response can be impacted by changing design features, and 2) once they have responded, this can have an impact on estimates after adjustment. The National Agricultural Statistics Service (NASS) is investigating the use of adaptive design techniques in the Crops Acreage, Production, and Stocks Survey (Crops APS). The Crops APS is a survey of establishments which vary in size and, hence, in their potential impact on estimates. In order to identify subgroups for targeted designs, we conducted a simulation study that used Census of Agriculture (COA) data as proxies for similar survey items. Different patterns of nonresponse were simulated to identify subgroups that may reduce estimated nonresponse bias when their response propensities are changed.

Nonresponse rates have been growing over time leading to concerns about survey data quality. Adaptive designs seek to allocate scarce resources by targeting specific subsets of sampled units for additional effort or a different recruitment protocol. In order to be effective in reducing nonresponse, the identified subsets of the sample need two key features: 1) their probabilities of response can be impacted by changing design features, and 2) once they have responded, this can have an impact on estimates after adjustment. The National Agricultural Statistics Service (NASS) is investigating the use of adaptive design techniques in the Crops Acreage, Production, and Stocks Survey (Crops APS). The Crops APS is a survey of establishments which vary in size and, hence, in their potential impact on estimates. In order to identify subgroups for targeted designs, we conducted a simulation study that used Census of Agriculture (COA) data as proxies for similar survey items. Different patterns of nonresponse were simulated to identify subgroups that may reduce estimated nonresponse bias when their response propensities are changed.

Memory analysis allows forensic investigators to establish a more complete timeline of system activity using a snapshot of main memory (i.e., RAM). Investigators may rely on such analysis to detect malicious activity and understand the scope of what data was exfiltrated. This is of particular interest in the presence of incomplete or untrusted logs, where a privileged user (or an attacker with such capabilities) can altogether bypass or disable logging. In such instances, a forensic investigator can still rely on the fact that data must ultimately be processed in memory, regardless of the information that is recorded in audit logs.

This study attempted to integrate key assumptions in Respondent-Driven Sampling (RDS) into the Total Survey Error (TSE) perspectives and examine TSE as a new framework for a systematic assessment of RDS errors. Using two publicly available data sets on HIV-at-risk persons, nonresponse error in the RDS recruitment process and measurement error in network size reports were examined. On nonresponse, the ascertained partial nonresponse rate was high, and a substantial proportion of recruitment chains died early. Moreover, nonresponse occurred systematically: recruiters with lower income and higher health risks generated more recruits; and peers of closer relationships were more likely to accept recruitment coupons. This suggests a lack of randomness in the recruitment process, also shown through sizable intra-chain correlation. Self-reported network sizes suggested measurement error, given their wide dispersion and unreasonable reports. This measurement error has further implications for the current RDS estimators, which use network sizes as an adjustment factor on the assumption of a positive relationship between network sizes and selection probabilities in recruitment. The adjustment resulted in nontrivial unequal weighting effects and changed estimates in directions that were difficult to explain and, at times, illogical. Moreover, recruiters’ network size played no role in actual recruitment. TSE may serve as a tool for evaluating errors in RDS, which further informs study design decisions and inference approaches.

This study attempted to integrate key assumptions in Respondent-Driven Sampling (RDS) into the Total Survey Error (TSE) perspectives and examine TSE as a new framework for a systematic assessment of RDS errors. Using two publicly available data sets on HIV-at-risk persons, nonresponse error in the RDS recruitment process and measurement error in network size reports were examined. On nonresponse, the ascertained partial nonresponse rate was high, and a substantial proportion of recruitment chains died early. Moreover, nonresponse occurred systematically: recruiters with lower income and higher health risks generated more recruits; and peers of closer relationships were more likely to accept recruitment coupons. This suggests a lack of randomness in the recruitment process, also shown through sizable intra-chain correlation. Self-reported network sizes suggested measurement error, given their wide dispersion and unreasonable reports. This measurement error has further implications for the current RDS estimators, which use network sizes as an adjustment factor on the assumption of a positive relationship between network sizes and selection probabilities in recruitment. The adjustment resulted in nontrivial unequal weighting effects and changed estimates in directions that were difficult to explain and, at times, illogical. Moreover, recruiters’ network size played no role in actual recruitment. TSE may serve as a tool for evaluating errors in RDS, which further informs study design decisions and inference approaches.

Interest in a multimode approach to surveys has grown substantially in recent years, in part due to increased costs of face-to-face (FtF) interviewing and the emergence of the Internet as a survey mode. Yet, there is little systematic evidence of the impact of a multimode approach on survey costs and errors. This article reports the results of an experiment designed to evaluate whether a mixed-mode approach to a large screening survey would produce comparable response rates at a lower cost than an FtF screening effort. The experiment was carried out in the Health and Retirement Study (HRS), an ongoing panel study of Americans over age 50. In 2010, HRS conducted a household screening survey to recruit new sample members to supplement the existing sample. The experiment varied the sequence of modes with which the screening interview was delivered. One treatment offered mail first, followed by FtF interviewing; the other started with FtF and then mail. A control group was offered only FtF interviewing. Results suggest that the mixed-mode options reduced costs without reducing response rates to the screening interview. There is some evidence, however, that the sequence of modes offered may impact the response rate for a follow-up in-depth interview.

The article presents information on the court holding of the Supreme Court of the U.S. regarding the reflection of the value of the property under the eminent domain proceeding by the condemning body that has paid the compensation. The condemned property is valued by the trial courts under the common law of Illinois. Information on the role of the Code of Civil Procedure regarding the valuation of the condemned property in Illinois is also presented.

Widespread vitamin D insufficiency and vitamin D supplementation (even low dose rickets prophylaxis) have been hypothesised as contributory factors to the recent increase in asthma. These hypotheses are supported by reports of immunomodulatory effects of vitamin D on antigen presenting cells, regulatory T cells and T-helper cells and evidence that vitamin D influences fetal lung differentiation and epithelial-mesenchymal function. Studies of vitamin D in animal models confirm complex effects of vitamin D on asthma immunopathogenesis. In humans a majority of epidemiological studies support the hypothesis that vitamin D insufficiency during pregnancy increases the likelihood of childhood wheeze and possibly asthma, although some studies do report the converse. In children and adults with asthma, reduced serum vitamin 25-hydroxyvitamin D levels have been associated with parameters of increased asthma severity. Clinical trials are underway addressing whether maternal vitamin D supplementation during pregnancy reduces the likelihood of childhood asthma and if there is a role for vitamin D supplementation in established asthma.

There is almost no data describing the long-term functional outcome of patients after penetrating cardiac injury.

Objective To report on 6 weeks of daptomycin treatment for tricuspid valve endocarditis caused by Staphylococcus aureus in a pregnant female in her second trimester.Case summary A 24-year-old, 14-week pregnant patient with no significant medical history, but with a history of intravenous drug abuse presented with tricuspid valve endocarditis caused by methicillin-sensitive S. aureus. After initial treatment with vancomycin, the patient continued to have fever and bacteremia and was initiated on daptomycin 6 mg/kg for 6 weeks of therapy. The treatment resulted in the resolution of the endocarditis, and no adverse sequelae were identified in the mother or baby.Discussion Infective endocarditis is a common infection encountered in the hospital setting and represents an increased cost burden to institutions due to prolonged lengths of treatment. Antimicrobial resistance, antimicrobial failure, inadequate attainment of effective drug concentrations, drug allergies, and adverse reactions may be factors that limit the use of commonly utilized antimicrobial agents. Therefore, newer therapies like daptomycin may need to be employed in these situations. Although daptomycin is pregnancy category B, limited case reports with neonatal outcomes are reported.Conclusions This case provides further support for the safety of daptomycin in pregnancy with the dose of 6 mg/kg, the extended duration of therapy (6 weeks), and the primary exposure in the second trimester.

In the long history of liberal learning and higher education, proponents of recent additions to the list of broadly accepted academic disciplines have had to overcome biases on the part of the academic establishment, on the one hand, and, on the other hand, have had to become willing to endure full intellectual access to and criticism of their field. Proponents of academic psychoanalysis face similar challenges today.

In the long history of liberal learning and higher education, proponents of recent additions to the list of broadly accepted academic disciplines have had to overcome biases on the part of the academic establishment, on the one hand, and, on the other hand, have had to become willing to endure full intellectual access to and criticism of their field. Proponents of academic psychoanalysis face similar challenges today.

Neutrophil (polymorphonuclear leukocyte PMN) migration into pulmonary airspaces is a prerequisite for clearance of bacteria commonly found in nosocomial pneumonia. Patients at risk for nosocomial pneumonia often experience endotoxemia, and neutrophil dysfunction is associated with endotoxemia in both humans and animals. Using a rodent model of endotoxemia-associated pneumonia, we characterized the altered kinetics of pulmonary PMN trafficking and addressed the roles of platelets, tumor necrosis factor (TNF), and products of complement activation as potential mediators in the modulation of PMN migratory function. In male Sprague-Dawley rats made endotoxemic with intravenously (i.v.) administered endotoxin (lipopolysaccharide LPS), recruitment of PMNs into the lung airspaces in response to intratracheally (i.t.) instilled LPS was inhibited. In animals given IT LPS alone (0.5 mg/rat), numbers of airway PMNs were significantly elevated by 2 h, and immunohistochemical evaluation revealed PMNs in alveolar airspaces, alveolar walls, and in interstitium surrounding large airways. LPS (2 mg/kg i.v.) caused neutropenia and pulmonary PMN sequestration within 15 min of administration. Inhibition of airway PMN accumulation occurred by 30 min and lasted for at least 6 h after i.v. LPS. Factors present or activated after 30 min of endotoxemia were hypothesized to mediate the inhibitory effect of i.v. LPS. We found that pretreatment of rats with cobra venom factor to deplete complement (and C5a production) or immunodepletion of platelets or TNF did not affect the ability of i.v. LPS to inhibit pulmonary PMN recruitment or to cause pulmonary leukostasis. In summary, our results show that the inhibitory effects of i.v. LPS on PMN trafficking are rapid and persist for several hours and suggest that neither TNF, C5a, nor platelets are sufficient to mediate the inhibitory response.

Endotoxemia is marked by a global activation of inflammatory responses, which can lead to shock, multiple organ failure, and the suppression of immune and wound healing processes. Neutrophils (PMNs) play a central role in some of these responses by accumulating in tissues and releasing reactive oxygen species and proteases that injure host structures. This review focuses on altered PMN migratory responses that occur during endotoxemia and their consequences in the development of pulmonary infection. The inflammatory mediators that might be responsible for these altered responses are discussed. The oxidant potential of PMNs is increased after exposure to endotoxin both in vitroand during clinical and experimental endotoxemia. However, other functions such as chemotaxis and phagocytosis are often depressed in these same cells. Endotoxin exposure renders PMNs hyperadhesive to endothelium. The sum of these effects produces activated inflammatory cells that are incapable of leaving the vasculature. As such, the endotoxic PMN is more likely to promote tissue injury from within microvascular beds than to clear pathogens from extravascular sites. Moreover, the functional characteristics of endotoxic PMNs are similar to those observed during trauma, burn injury, sepsis, surgery, and other inflammatory conditions. Accordingly, several clinical conditions might have a common effector in the activated, yet migratorially dysfunctional, PMN. Direct effects of endotoxin on PMNs as well as effects of endogenous mediators released during endotoxemia are discussed. Understanding PMN behavior during endotoxemia may provide basic and critical insights that can be applied to a number of inflammatory scenarios. J. Leukoc. Biol.66: 10–24; 1999.

A novel laser system has been designed and developed for the time-resolved holographic analysis of dynamic crack propagation in thin (150 µm) glass plates. The system provides a frame-to-frame resolution of from 28.3 to 161.6 ns, with a spatial resolution of better than 25 µm. Holographic analyses were conducted using both diffuse and direct laser illumination, demonstrating a broad range of applicability for this method. A series of specimens with pre-crack lengths of from 3.5 to 10.5 mm were tested using various pre-load levels and crack-growth-initiating explosive sizes. All specimens exhibited similar dynamic fracture behavior, particularly those outside of the region of shock of the initiating explosive (those of the longer pre-crack set). A best-fit to the theoretical prediction for mode I crack growth revealed a good match to the case for a specimen ‘overloaded’ by 64 percent. However, no variation with applied load was evident, indicating that an immediate acceleration to a velocity of ˜ 1200 m/s (near the empirically determined terminal velocity) was the more plausible fit. Since the terminal velocity was approximately the same for all specimens, this investigation also demonstrated that the terminal velocity is independent of crack-tip stresses, even for the most extreme explosive pulses.

The Information Systems Division of the University of Iowa Hospitals and Clinics has successfully designed and implemented a set of generalized interface data-handling routines that control message traffic between a satellite minicomputer in a clinical laboratory and a large main-frame computer. A special queue status inquiry transaction has also been developed that displays the current message-processing backlog and other system performance information. The design and operation of these programs are discussed in detail, with special emphasis on the message-queuing and verification techniques required in a distributed processing environment.