A Public BCR Present in a Unique Dual-Receptor-Expressing Lymphocyte from Type 1 Diabetes Patients Encodes a Potent T Cell Autoantigen.

T and B cells are the two known lineages of adaptive immune cells. Here, we describe a previously unknown lymphocyte that is a dual expresser (DE) of TCR and BCR and key lineage markers of both B and T cells. In type 1 diabetes (T1D), DEs are predominated by one clonotype that encodes a potent CD4 T cell autoantigen in its antigen binding site. Molecular dynamics simulations revealed that this peptide has an optimal binding register for diabetogenic HLA-DQ8. In concordance, a synthetic version of the peptide forms stable DQ8 complexes and potently stimulates autoreactive CD4 T cells from T1D patients, but not healthy controls. Moreover, mAbs bearing this clonotype are autoreactive against CD4 T cells and inhibit insulin tetramer binding to CD4 T cells. Thus, compartmentalization of adaptive immune cells into T and B cells is not absolute, and violators of this paradigm are likely key drivers of autoimmune diseases.

Neighborhood Conditions and Social Network Turnover among Older Adults.

Increasing research highlights heterogeneity in patterns of social network change, with growing evidence that these patterns are shaped in part by social structure. The role of social and structural neighborhood conditions in the addition and loss of kin and non-kin network members, however, has not been fully considered. In this paper, we argue that the residential neighborhood context can either facilitate or prevent the turnover of core network relationships in later life - a period of the life course characterized by heightened reliance on network ties and vulnerability to neighborhood conditions. Using longitudinal data from the National Social Life, Health, and Aging Project linked with data from the American Community Survey, we find that higher levels of neighborhood concentrated disadvantage are associated with the loss of older adults' kin and non-kin network members over time. Higher levels of perceived neighborhood social interaction, however, are associated with higher rates of adding non-kin network members and lower rates of adding kin network members over time. We suggest that neighborhood conditions, including older adults' perceptions of neighborhood social life, represent an underexplored influence on kin and non-kin social network dynamics, which could have implications for access to social resources later in the life course.

Sequence analysis: Its past, present, and future.

This article marks the occasion of Social Science Research's 50th anniversary by reflecting on the progress of sequence analysis (SA) since its introduction into the social sciences four decades ago, with focuses on the developments of SA thus far in the social sciences and on its potential future directions. The application of SA in the social sciences, especially in life course research, has mushroomed in the last decade and a half. Using a life course analogy, we examined the birth of SA in the social sciences and its childhood (the first wave), its adolescence and young adulthood (the second wave), and its future mature adulthood in the paper. The paper provides a summary of (1) the important SA research and the historical contexts in which SA was developed by Andrew Abbott, (2) a thorough review of the many methodological developments in visualization, complexity measures, dissimilarity measures, group analysis of dissimilarities, cluster analysis of dissimilarities, multidomain/multichannel SA, dyadic/polyadic SA, Markov chain SA, sequence life course analysis, sequence network analysis, SA in other social science research, and software for SA, and (3) reflections on some future directions of SA including how SA can benefit and inform theory-making in the social sciences, the methods currently being developed, and some remaining challenges facing SA for which we do not yet have any solutions. It is our hope that the reader will take up the challenges and help us improve and grow SA into maturity.

Patterns of everyday activities across social contexts.

Social-scientific theory and research give rise to conflicting expectations regarding the extent to which individuals' everyday lives in modern society follow predictable patterns of behavior. Much previous research has addressed this issue implicitly by documenting widespread trends in patterns of "time use" or "time allocation," including trends in time devoted to paid work, unpaid work, and leisure. This study expands on this research by examining common patterns with respect to not how much time individuals spend on certain everyday activities (e.g., leisure), but rather how those activities are sequenced throughout the day. Using sequence methods and cluster analysis, we analyze a large collection of harmonized time diaries from the Multinational Time Use Study (MTUS), including diaries from 23 countries and dating back to 1961. Our analysis of these diaries reveals eight common everyday sequence patterns-including different paid work, unpaid work, and leisure clusters. This same set of patterns reappears in a generally similar distribution across the different countries and time periods that are included in the MTUS sequence data. This study has implications for how analysts study time diary data and raises important questions about the causes and consequences of individuals' experiences with particular behavioral sequences.

Tied Infections: How Social Connectedness to Other COVID-19 Patients Influences Illness Severity.

Expanding on recent research on the transmission of COVID-19 via social networks, this article argues that exposure to familial and other close contacts who already have the disease may increase the severity of one's subsequent illness. We hypothesize that having family members or close contacts who were diagnosed with COVID-19 before one's own diagnosis exacerbates illness severity due to several potential mechanisms including changes in available social support access, increased stress and strain, and increased viral load due to the nature of one's exposure to the novel coronavirus. We analyze administrative data of all 417 patients who were diagnosed with COVID-19 in the Chinese city of Shenzhen between January 8 and February 25, 2020. Our analyses show that, when patients had family members or close ties diagnosed with COVID-19, they experienced more severe illness. We also find that patients with infected family members or close contacts did not have significantly extended total illness duration, due to their reduced time to diagnosis. The implications of both findings are discussed.

Implications of Mothers' Social Networks for Risky Infant Sleep Practices.

OBJECTIVE: To describe the structure of networks in a cohort of mothers and to analyze associations of social network characteristics and norms with infant sleep practices. STUDY DESIGN: We recruited a prospective cohort of mothers with infants <6 months of age from January 2015 to December 2016. Mothers completed a survey about their personal social networks and infant care practices. Latent class analysis identified unobserved network types. Binary statistics and path analysis were performed. RESULTS: Overall, 402 mothers were surveyed. Latent class analysis identified 2 a priori unknown social network types: "exclusive" (restricted) and "expansive." Mothers who were black, younger, unmarried, less educated, and of lower socioeconomic status were more likely to have exclusive networks than expansive networks. Mothers with exclusive networks were more likely to be exposed to the norm of soft bedding (P = .002). Exposure to norms of non-supine infant placement, bedsharing, and soft bedding use within one's network was associated with engaging in these practices (P < .0001 for each). First-time mothers were more likely to pay attention to a non-supine norm and place infants in a non-supine position. Black mothers and first-time mothers were more likely to pay attention to the norm and use soft bedding. CONCLUSIONS: Both the type of networks mothers have and the norms regarding infant sleep practices that circulate within these networks differed by race. Network norms were strongly associated with infant sleep practices and may partially explain the racial disparity therein.

A Longitudinal Examination of Factors Associated with Network Bridging Among YMSM: Implications for HIV Prevention.

Social-environmental factors may be associated with social network stability, which has implications for HIV acquisition. However, the link between social-environmental factors, network composition and HIV risk has not been examined previously among a city-population based sample of young Black men who have sex with Men (YBMSM). Respondent driven sampling was used to recruit a cohort of 618 YMBSM. Respondents were evaluated at baseline, 9 and 18 months beginning June 2013. A logistic regression model was used to assess the relationship between bridging (i.e. having non-redundant contacts in one's network, indicating network instability) and social-environmental factors and HIV risk factors between respondents, and a conditional logit model was used to assess these relationships within respondents over time. Bridging was associated with adverse social-environmental factors and higher HIV risk, indicating that bridging may be on the explanatory pathway. Future studies should assess the extent to which network stability factors mitigate HIV risk.

Pediatric Central Nervous System Imaging of Nonaccidental Trauma: Beyond Subdural Hematomas.

Infants and children under 2 years of age are at greatest risk for devastating neurologic complications following nonaccidental trauma. While a subdural hematoma (SDH) is the most common finding and is often enough to raise suspicion for abuse, no single injury is pathognomonic for abusive head trauma (AHT). Rather, the combination of imaging and physical findings and the clinical presentation help confirm the diagnosis of AHT. Familiarity with the spectrum of findings and proper identification of the imaging abnormalities is important for the radiologist to facilitate treatment and removal of the patient from the abusive environment. Injury is usually a result of shaking, which includes hyperflexion, hyperextension, and rotational forces, and less commonly impact trauma or a combination of both. Key anatomic features unique to the infant's head, neck, and spine and associated biomechanical forces are responsible for entities such as hypoxic ischemic injury, bridging vein thrombosis, SDH, parenchymal lacerations, and spinal and retinal injuries. Although the association of subpial hemorrhage with AHT has not been investigated, it warrants attention in very young infants who endure accidental or inflicted trauma. A combination of CT of the head and MRI of the brain and cervical spine aids in the accurate diagnosis, appropriate management, and subsequent protection of these patients. ©RSNA, 2018.

Patterns of Social Affiliations and Healthcare Engagement Among Young, Black, Men Who Have Sex With Men.

Little work has examined how individuals' social affiliations-the venues in which they meet friends and engage in informal social interaction-influence their engagement with public health services. We investigate how links to these local places shape access to information and exposure to health-seeking behavior. Using longitudinal data from a respondent-driven sample of 618 young black men who have sex with men (YBMSM) in Chicago, we identify different sets of social venues that connect YBMSM. We then examine how YBMSM's connections within this network influence their receipt of HIV prevention and treatment services and knowledge of pre-exposure prophylaxis (PrEP). Our results show that YBMSM's positions within Chicago's venue network shape the types of health-related services they access, net of demographic, structural, and community covariates. Men with affiliations that are linked to the city's gay enclave are most likely to know about PrEP, while men with affiliations that are predominately in the black community demonstrate improved HIV treatment outcomes. Outreach engaging MSM beyond venues in gay enclaves is needed.

Marijuana Use Among Young Black Men Who Have Sex With Men and the HIV Care Continuum: Findings From the uConnect Cohort.

BACKGROUND: Young Black men who have sex with men (YBMSM) are at highest risk for HIV seroconversion in the United States. Successful movement through the HIV care continuum is an important intervention for limiting onwards HIV transmission. OBJECTIVE: Little data exists on how substances most commonly used by YBMSM, such as marijuana, are related to the HIV continuum, which represents the primary aim of this study. METHODS: A cohort of YBMSM (n = 618) was generated through respondent-driven sampling. Frequency of marijuana use and marijuana use as a sex-drug were assessed across the HIV care continuum using weighted logistic regression models. RESULTS: Study participants reported more intermittent marijuana use (n = 254, 56.2%) compared to heavy use (n = 198, 43.8%). Our sample contained 212 (34.3%) HIV seropositive participants of which 52 (24.5%) were unaware of their HIV positive status. Study participants who were heavy marijuana users were more likely to be unaware of their HIV seropositive status (AOR: 4.18; 95% CI 1.26, 13.89). All other stages in the care continuum demonstrated no significant differences between those who use marijuana intermittently or heavily or as a sex-drug and nonusers. CONCLUSIONS: YBMSM who used marijuana heavily were more likely to be HIV-positive unaware than those who never used marijuana. Findings were inconclusive regarding the relationships between marijuana use and other HIV care continuum metrics. However, knowledge of ones' HIV status is a critical requirement for engaging in care and may have implications for onwards HIV transmission.

The Social Connectedness of Older Adults during the COVID-19 Pandemic: Evidence by Survey Mode and Respondent Dementia.

OBJECTIVES: The COVID-19 pandemic has affected many aspects of social life, especially among older adults who may face cognitive impairments. Concerning this combination of circumstances, the study evaluates the degree to which data collection on social connectedness among older adults might be affected by the social complexities of the COVID-19 pandemic. METHOD: We use data from the National Social Life, Health and Aging Project (NSHAP), a nationally representative study of community-dwelling older adults in the U.S., which conducted a special multi-mode COVID study between September 2020 and January 2021, in part to examine social impacts of the COVID-19 pandemic and to assess how alternative survey modes performed during the pandemic. Our final sample includes 2,251 older adults, ages 55 and older. RESULTS: Older adults' social connectedness was adversely affected by the pandemic. People reported a tendency to move toward electronic communication and away from in-person contact. Concomitantly, there is some evidence of survey mode effects that are related to electronic communication. Those who elected to participate on the phone, or the internet disproportionately reported using those means of communication with their social network members. Notably, this pattern was stronger among those who did not suffer from dementia, suggesting cognition effects on survey completion. DISCUSSION: Researchers should remain cognizant of how data on social connections were collected during the COVID-19 pandemic. These findings may indicate the role dementia plays in preventing people from adapting to new social networking realities with alternative means of communication during the pandemic.

Network mixing and network influences most linked to HIV infection and risk behavior in the HIV epidemic among black men who have sex with men.

OBJECTIVES: We evaluated network mixing and influences by network members upon Black men who have sex with men. METHODS: We conducted separate social and sexual network mixing analyses to determine the degree of mixing on risk behaviors (e.g., unprotected anal intercourse [UAI]). We used logistic regression to assess the association between a network "enabler" (would not disapprove of the respondent's behavior) and respondent behavior. RESULTS: Across the sample (n = 1187) network mixing on risk behaviors was more assortative (like with like) in the sexual network (r(sex), 0.37-0.54) than in the social network (r(social), 0.21-0.24). Minimal assortativity (heterogeneous mixing) among HIV-infected men on UAI was evident. Black men who have sex with men reporting a social network enabler were more likely to practice UAI (adjusted odds ratio = 4.06; 95% confidence interval = 1.64, 10.05) a finding not observed in the sexual network (adjusted odds ratio = 1.31; 95% confidence interval = 0.44, 3.91). CONCLUSIONS: Different mixing on risk behavior was evident with more disassortativity among social than sexual networks. Enabling effects of social network members may affect risky behavior. Attention to of high-risk populations' social networks is needed for effective and sustained HIV prevention.

Switching Dynamics and the Stress Process.

This paper shows how maintaining social relationships can be a daily hassle that has implications for the stress process, depending on how often individuals transition, or "switch," between their various social roles and social settings throughout the day. I use nationally representative time diary data on 7,662 respondents from the 2010 American Time Use Survey to measure individual rates of this switching behavior and to examine how this relates to perceived stress. Regression analysis shows that, net of how many social roles they play and settings they visit on a given day, individuals who switch more frequently between these elements report higher levels of stress. This finding holds for women but not men, suggesting that switching dynamics are disproportionately stressful for women. I close by discussing the implications of the findings for research on gender and health.

"I Love You to Death": Social Networks and the Widowhood Effect on Mortality.

Research on "the widowhood effect" shows that mortality rates are greater among people who have recently lost a spouse. There are several medical and psychological explanations for this (e.g., "broken heart syndrome") and sociological explanations that focus on spouses' shared social-environmental exposures. We expand on sociological perspectives by arguing that couples' social connections to others play a role in this phenomenon. Using panel data on 1,169 older adults from the National Social Life, Health, and Aging Project, we find that mortality is associated with how well embedded one's spouse is in one's own social network. The widowhood effect is greater among those whose spouses were not well connected to one's other network members. We speculate that the loss of a less highly embedded spouse signals the loss of unique, valuable, nonredundant social resources from one's network. We discuss theoretical interpretations, alternative explanations, limitations, and directions for future research.

Social network-structural position and obesity: Evidence from a national study.

This study expands on research on the social-structural bases of obesity by examining the role played by individuals' positions within their egocentric social networks in shaping body mass index. We argue that individuals' tendency to be a bridge between otherwise unconnected people can affect body mass index. Furthermore, health-specific resources flowing through their networks might interact with this network-structural position to shape this association. Using multivariate analyses of recent nationally representative data on older Americans, we find that occupying a bridging position within a network is negatively related to the likelihood of being obese. Moreover, people who have this bridging potential tend to benefit more from health-related knowledge in their networks than those who do not have it. Our findings underscore the importance of considering social network position and the functional specificity of ties in understanding the structural bases of health problems like obesity. We close by discussing implications of these findings for future work on obesity including potential insights into important health disparities.

HIV health center affiliation networks of black men who have sex with men: disentangling fragmented patterns of HIV prevention service utilization.

BACKGROUND: In the United States, black men who have sex with men (BMSM) are at highest risk for HIV infection and are at high risk for limited health service utilization. We describe HIV health center (HHC) affiliation network patterns and their potential determinants among urban BMSM. METHODS: The Men's Assessment of Social and Risk Network instrument was used to elicit HHC utilization, as reported by study respondents recruited through respondent-driven sampling. In 2010, 204 BMSM were systematically recruited from diverse venues in Chicago, IL. A 2-mode data set was constructed that included study participants and 9 diverse HHCs. Associations between individual-level characteristics and HHC utilization were analyzed using Multiple Regression Quadratic Assignment Procedure. Visualization analyses included computation of HHC centrality and faction membership. RESULTS: High utilization of HHCs (45.9%-70.3%) was evident among BMSM, 44.4% who were HIV infected. Multiple Regression Quadratic Assignment Procedure revealed that age, social network size, and HIV status were associated with HHC affiliation patterns (coeff., 0.13-0.27; all P < 0.05). With the exception of one HHC, HHCs offering HIV prevention services to HIV-infected participants occupied peripheral positions within the network of health centers. High-risk HIV-uninfected participants affiliated most with an HHC that offers only treatment services. CONCLUSIONS: Subcategories of BMSM in this sample affiliated with HHCs that may not provide appropriate HIV prevention services. Using 2-mode data, public health authorities may be better able to match prevention services to BMSM need; in particular, HIV prevention services for high-risk HIV-uninfected men and HIV "prevention for positives" services for HIV-infected men.

Robot-Assisted Thoracolumbar Fixation After Acute Spinal Trauma: A Case Series.

BACKGROUND: Pedicle screw fixation has become the workhorse for the stabilization of the thoracolumbar spine. Since accurate pedicle screw placement is necessary for a successful surgery, three-dimensional navigation has become a mainstay for placing pedicle screws. However, the published studies have an overrepresentation of lumbar screws despite the prevalence of thoracic fractures. Furthermore, no robotic-assisted pedicle screw study has focused solely on traumatic fractures. The goal of this study was to address whether (1) robot-assisted pedicle screw placement had comparable accuracy in the thoracic and thoracolumbar region and (2) robot-assisted spine surgery was feasible in an acute, traumatic setting. METHODS: We performed 14 consecutive, thoracolumbar spinal stabilization procedures in which 126 pedicle screws were placed using the Globus ExcelsiusGPS® spine robot in an acute, traumatic setting. Operative times were measured, and the accuracy of pedicle screws was assessed with the Gertzbein and Robbins classification system by two board-certified neuroradiologists. RESULTS: A total of 60-thoracic (T3-T11), the 24-thoracolumbar junction (T12-L1), 40-lumbar (L2-L5), and two-sacral pedicle screws were placed. Pedicle screw placement was accurate with a < 1% (1/126) pedicle breach rate. Thoracolumbar robotic spine surgery in an acute, traumatic setting was demonstrated to have a good safety profile with only one minor neurological deficit which was related to positioning. Furthermore, surgical times were inversely related to the case number. CONCLUSIONS: These results together suggest that robot-assisted spine surgery is accurate in the thoracic spine. Furthermore, placement of thoracolumbar screws in an acute trauma is non-inferior to other methods when based on accuracy.

Associations between general practice characteristics and chest X-ray rate: an observational study.

BACKGROUND: Chest X-ray (CXR) is the first-line test for lung cancer in many settings. Previous research has suggested that higher utilisation of CXR is associated with improved outcomes. AIM: To explore the associations between characteristics of general practices and frequency of investigation with CXR. DESIGN AND SETTING: Retrospective observational study of English general practices. METHOD: A database was constructed of English general practices containing number of CXRs requested and data on practices for 2018, including patient and staff demographics, smoking prevalence, deprivation, and patient satisfaction indicators. Mixed-effects Poisson modelling was used to account for variation because of chance and to estimate the amount of remaining variation that could be attributed to practice and population characteristics. RESULTS: There was substantial variation in GP CXR rates (median 34 per 1000 patients, interquartile range 26-43). Only 18% of between-practice variance in CXR rate was accounted for by recorded characteristics. Higher practice scores for continuity and communication skills, and higher proportions of smokers, Asian and mixed ethnic groups, and patients aged >65 years were associated with increased CXR rates. Higher patient satisfaction scores for access and greater proportions of male patients and patients of Black ethnicity were associated with lower CXR rates. CONCLUSION: Substantial variation was found in CXR rates beyond that expected by chance, which could not be accounted for by practices' recorded characteristics. As other research has indicated that increasing CXR rates can lead to earlier detection, supporting practices that currently investigate infrequently could be an effective strategy to improve lung cancer outcomes.

Torcular pseudomass in a 14-month-old child: illustrative case.

BACKGROUND: "Torcular pseudomass," or redundant soft tissue in the torcular region, is not an infrequent incidental finding on advanced imaging of the brain in infants and young children. It was recently codified among pediatric neuroradiologists; however, its report in the pediatric neurosurgical community has not previously been elucidated. OBSERVATIONS: The authors present a case of a 14-month-old child who presented with fever and a first-time seizure. Computed tomography of the head suggested an epidural abscess; however, magnetic resonance imaging characteristics of the lesion were consistent with torcular pseudomass, a normal variant. At the 3-month follow-up, the child was continuing to do well and had not had another seizure. There have been no indications for surgical intervention or additional radiographic surveillance. LESSONS: The differential diagnosis for torcular pseudomass includes dural venous sinus thrombosis, dermoid cysts, occipital encephalocele, eosinophilic granuloma, and primary and metastatic tumors, such as neuroblastoma. The management of each of these disorders in the differential diagnosis may be much more invasive than continued observation in the case of torcular pseudomass. Therefore, it is important for pediatric neurosurgeons to become familiar with this developmental anomaly of the dura and occipital skull.

Homeostasis Revisited: Patterns of Stability and Rebalancing in Older Adults' Social Lives.

OBJECTIVES: To examine patterns of change in later-life social connectedness: (a) the extent and direction of changes in different aspects of social connectedness, including size, density, and composition of social networks, network turnover, and three types of community involvement and (b) the sequential nature of these changes over time. METHOD: We use three waves of nationally representative data from the National Social Life, Health, and Aging Project, collected from 2005/2006 to 2015/2016. Respondents were between the ages of 67 and 95 at follow-up. Types of changes in their social connectedness between the two successive 5-year periods are compared to discern over-time change patterns. RESULTS: Analyses reveal stability or growth in the sizes of most older adults' social networks, their access to non-kin ties, network expansiveness, as well as several forms of community involvement. Most older adults experienced turnover within their networks, but losses and additions usually offset each other, resulting in generally stable network size and structural features. Moreover, when older adults reported decreases (increases) in a given form of social connectedness during the first half of the study period, these changes were typically followed by countervailing increases (decreases) over the subsequent 5-year period. This general pattern holds for both network and community connectedness. DISCUSSION: There is an overwhelming tendency toward either maintaining or rebalancing previous structures and levels of both personal network connectedness and community involvement. This results in overall homeostasis. We close by discussing the need for a unifying theoretical framework that can explain these patterns.