DC Area Research Articles

Operation of the full‐bridge three‐level DC–DC converter in unbalanced bipolar DC microgrids

As compared to two-wire, unipolar DC microgrids (DCμGs), bipolar DCμGs apply a positive, neutral and negative conductor to increase the power transfer capability while retaining two voltage levels for supplying low- and high-power devices at an appropriate voltage. However, connecting devices between the positive or negative pole and the neutral conductor will result in unbalanced currents causing voltage to unbalance. Therefore, power electronic converters with voltage balancing capability are essential. Instead of installing dedicated voltage balancing converters, this study proposes to apply three-level DC–DC converters. These converters can interface battery storage with bipolar DCμGs and balance the pole-to-neutral voltages at the same time. However, high levels of unbalanced currents drive three-level DC–DC converters towards their theoretical unbalanced operating limits. To derive these, a method is presented which decomposes the governing equations in balanced and unbalanced components. Although the method is generally applicable to the three-level converters, the full-bridge three-level converter serves as a comprehensive example. The method enables to derive the unbalanced operating area of three-level DC–DC converters and to appropriately size the filter inductor. Furthermore, a novel modulation strategy is introduced in order to lower the inductor current ripple in unbalanced conditions, supported by experimental results.

A Community-Based Participatory Approach to Understanding HIV/AIDS in the Ethiopian Community

ABSTRACTThe rate of HIV/AIDS in Washington, D.C remains at epidemic levels and is most prevalent in the black community, with foreign-born blacks accounting for an increasing proportion of HIV infections in the Washington DC area. The Ethiopian community is among the subgroups that are especially impacted by HIV/AIDS. Yet, seldom does research on the epidemiology of HIV/AIDS break data into diverse subgroups, accounting for the distinct needs based on cultural or ethnic differences. This paper reports on the qualitative findings from a community participatory action research study that involved interviewing 60 Ethiopian-immigrants and nine community-based providers about their attitudes toward HIV/AIDS, and to elicit their ideas about how to improve HIV/AIDS prevention, promotion, and treatment approaches targeting the Ethiopian community. Findings show that stigma remains the largest barrier to accessing HIV/AIDS treatment among Ethiopians in the Washington, D.C. area. Therefore, strategies to reduce HIV/AIDS must address stigmatizing beliefs and be met with cultural sensitivity when developing community prevention and treatment outreach programs designed to reduce HIV/AIDS among Ethiopians.

Sociodemographic and Environmental Determinants of Indoor Versus Outdoor Active Play Among Children Living in the Washington, DC Area.

Sociodemographic and environmental factors play important roles in determining both indoor and outdoor play activities in children. The Built Environment and Active Play Study assessed neighborhood playability for children (7-12y), based on parental report of their children's active play behaviors, neighborhood characteristics, and geographic locations. Simple logistic regression modeling tested the associations between sociodemographic characteristics and the frequency of and access to venues for indoor and outdoor play. Children of higher socioeconomic status were almost 3 times more likely to live more than a 30-minute walk from indoor recreational facilities compared with their less affluent peers (odds ratio [OR] = 2.9; 95% confidence interval [CI], 1.2-6.8). Non-Hispanic black children were less likely to live more than 30 minutes from indoor facilities (OR = 0.21; 95% CI, 0.08-0.57) and more were likely to engage in indoor activity (OR = 3.40; 95% CI, 1.17-9.88) than were white children. Boys were substantially more likely to play outdoors at a playing fields compared with girls (OR = 5.37; 95% CI, 2.10-13.69). Findings from this study could be used to enhance indoor and outdoor activity spaces for children and to reduce disparities in access to such spaces.

Multi-objective optimal operation of hybrid AC/DC microgrid considering source-network-load coordination

Taking the consumption rate of renewable energy and the operation cost of hybrid AC/DC microgrid as the optimization objectives, the adjustment of load demand curves is carried out considering the demand side response (DSR) on the load side. The complementary utilization of renewable energy between AC area and DC area is achieved to meet the load demand on the source side. In the network side, the hybrid AC/DC microgrids purchase electricity from the power grid at the time-of-use (TOU) price and sell the surplus power of renewable energy to the power grid for profits. The improved memetic algorithm (IMA) is introduced and applied to solve the established mathematical model. The promotion effect of the proposed source-network-load coordination strategies on the optimal operation of hybrid AC/DC microgrid is verified.

1599-P: Glycated Albumin Identifies Dysglycemia Not Detected by A1C: The Case for Combining Glycated Albumin and A1C in Africans

As the diabetes (DM) epidemic spreads in Africa, affected adults are younger and less obese than in high-income regions of the world. A1C, a nonfasting marker of glycemia, is used to diagnose dysglycemia, a summary term for prediabetes and DM. However, independent of glycemia, A1C increases with age and BMI. Conversely, hemoglobinopathies common in Africa such as sickle cell trait (SCT) can lead to artefactually low A1C levels. Because of the challenges surrounding A1C, attention is turning to glycated albumin (GA). Our goal was to determine in Africans the value of A1C and GA when a) performed individually and b) combined. OGTT was performed and A1C and GA levels were measured in 366 African-born blacks currently living in the Washington, DC area (male: 67%). Diagnosis of dysglycemia was based on fasting glucose≥100 mg/dL or 2h glucose≥140 mg/dL. The ability of A1C≥5.7% and GA≥14.2% to diagnose dysglycemia was evaluated. Both A1C≥5.7% and GA≥14.2% represent the upper quartile cut-off for their distribution in the population. To assess the value of performing both GA and A1C, people with dysglycemia were divided into 2 groups: 1) A1C-group detected by A1C only or A1C and GA; 2) GA-group identified by GA only and not detected by A1C. Dysglycemia occurred in 36% (135/366) of participants. SCT occurred in 17% (62/366) of the cohort and 20% (27/135) of people with dysglycemia. Sensitivities of A1C and GA were only 43% and 33%, resp. However, combining A1C and GA led to a sensitivity of 60% and this was better than either test alone (P<0.01). People identified by GA but not A1C were younger (age: 42±10 vs. 47±9y (mean±SD), P=0.05) and less obese (BMI: 26.7±2.5 vs. 30.3±4.5, P<0.01). A1C identified 52% (14/27) of the people with SCT and dysglycemia. GA identified an additional 22% (6/27) of people with SCT and dysglycemia not detected by A1C. Overall, combining GA with A1C leads to improved detection of dysglycemia in Africans from three groups: SCT, the nonobese and younger adults. Disclosure R. Mugeni: None. J.Y. Aduwo: None. S.M. Briker: None. M.F. Horlyck-Romanovsky: None. L. Mabundo: None. C. DuBose: None. A.E. Sumner: None.

1600-P: Duplicate Oral Glucose Tolerance Tests Reveal Excellent Reproducibility for Detection of Diabetes but Inconsistent Results for Prediabetes: A Study of Africans

As both diabetes (DM) and prediabetes (preDM) reach epidemic proportions in sub-Saharan Africa, there is growing need for reliable diagnostic tests. Although the OGTT is time-consuming, it is unaffected by hemoglobinopathies which are common in Africa and interfere with other methods of detection. However, the reproducibility of the OGTT in Africans is unknown. Therefore, our goal was to perform duplicate OGTTs in Africans and determine if the diagnosis made at the first OGTT was confirmed by the second. One-hundred and five African-born blacks (64% male (67/105), age 39±11y (mean±SD), BMI 27.4±4.5 kg/m2) living in the Washington, DC area had two OGTTs performed 11±7 days apart. Glucose tolerance status was defined by glucose criteria for the OGTT. κ-statistic was used to assess reproducibility (slight: 0.00 to 0.20; fair: 0.21 to 0.40; moderate: 0.41 to 0.60; substantial: 0.61 to 0.80, excellent: 0.81 to 1.0). At OGTT-1, DM, preDM and normal glucose tolerance (NGT) occurred in 23% (24/105), 26% (27/105) and 51% (54/105), resp. At OGTT-2, DM, preDM and NGT occurred in 19% (20/105), 26% (27/105) and 55% (58/105) resp. Reproducibility for the diagnosis of DM was excellent (κ=0.88). No one transitioned from DM to NGT. Further, all participants with DM at OGTT-2 had also been diagnosed with DM at OGTT-1. In contrast, reproducibility for the diagnosis of preDM was only moderate (κ=0.48). Between OGTT-1 and OGTT-2, 10% (11/105) of people transitioned from preDM to NGT; and 7% (7/105) transitioned from NGT to preDM. However, 78% (14/18) of the people who transitioned between NGT and preDM had fasting glucose levels between 90 and 99 mg/dL. Overall, as duplicate OGTTs provided highly reproducible results for the diagnosis of DM, detection of DM by a single OGTT should trigger health care consideration. Diagnosis of preDM was not consistent, but fasting glucose between 90 mg/dL and 99 mg/dL suggests that transition from NGT to preDM is likely. Disclosure S.M. Briker: None. M.F. Horlyck-Romanovsky: None. J.Y. Aduwo: None. R. Mugeni: None. C. DuBose: None. L. Mabundo: None. S.T. Chung: None. J. Ha: None. A. Sherman: None. A.E. Sumner: None.

1533-P: Detecting Diabetes in Africans Is Improved by Both Modifying the A1C Threshold and Adding Glycated Albumin

A1C at the standard threshold of 6.5% has been a poor predictor of diabetes (DM) in Africans. Reasons for the poor performance of A1C are myriad and include hemoglobinopathies and anemia. To begin to address challenges with A1C as a diagnostic test for Africans, there needs to be a determination that the threshold for A1C of 6.5% is appropriate. In addition, there could be value in determining if glycated albumin (GA), a non-fasting marker of glycemia not affected by hemoglobinopathies and anemia, would improve detection of DM. Therefore, we tested in Africans (a) the ability of A1C and GA independently and combined to predict DM and (b) the optimal cut-points for A1C and GA. OGTT were performed in 366 African-born blacks (age 38±10 (mean± SD); BMI 27.5 ±4.4 kg/m2) who self-identified as healthy and currently living in the Washington, DC area. Diagnosis of DM was based on glucose criteria for the OGTT. Ability of A1C and GA to predict DM was estimated by area under the receiver operating characteristic curve (AROC). Youden index established optimal cut-points for A1C and GA. Diabetes was newly diagnosed in 6% (23/366). For the prediction of DM by A1C the AROC was 0.78 (95% CI 0.68-0.88), and the optimal cut point was ≥5.8%. For the prediction of DM by GA the AROC was 0.73 (95% CI 0.61-0.85), and the optimal cut point was ≥14.05%. At these cut-points, DM was identified by A1C in 61% (14/23) (sensitivity 61%, specificity of 82%), and by GA in 65% (15/23) (sensitivity 65%, specificity 72%). The combination of A1C and GA identified DM in 83% (19/23) (sensitivity 83%, specificity 60%). Overall, the combination of A1C ≥5.8% and GA ≥14.05% markedly improved the detection of undiagnosed diabetes in Africans. Combining two non-fasting markers of glycemia at African-specific thresholds may be an important innovation in healthcare delivery. Disclosure R. Mugeni: None. S.M. Briker: None. J.Y. Aduwo: None. C. DuBose: None. A.E. Sumner: None. M.F. Horlyck-Romanovsky: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases; National Institute on Minority Health and Health Disparities

008 Examining Clinician Attitudes on Sexual Health Assessment after an Educational Intervention

It is estimated that 43% of women suffer from sexual dysfunction. Women expect their providers to evaluate their sexual health, yet most clinicians do not because they feel they do not have the time, training, or knowledge of treatment options. This discrepancy leaves many women with unaddressed health concerns. The purpose of the study was to 1) examine clinician attitudes before and after watching the evidence based educational video 2) examine the impact of each of the six educational domains individually and to 3) assess the correlation between the participants quality rating of each domain in the video and impact the on participants’ attitudes. A recruitment email was sent to one primary care practice and two ob/gyn practices in the Washington, DC area. They were asked to forward the survey to appropriate colleagues to widen and diversify the sample. Participants completed a 12 question pre-survey. A large majority watched a 15 minute evidence based educational video about women’s sexual health that included the following domains: how to ask and evaluate sexual health, how to address concerns, what a sexual medicine specialist/pelvic floor physical therapist/sexuality mental health professional does, and how to find them and available resources (organizations, websites, and continuing education). After watching the video, participants took a 17 question post-survey. Before and after t-scores demonstrated a significant improvement in provider willingness to evaluate sexual health.

Dynamic Source Model for the 2011 Tohoku Earthquake in a Wide Period Range Combining Slip Reactivation with the Short-Period Ground Motion Generation Process

This paper describes a validated dynamic rupture model of the 2011 Tohoku earthquake that reproduces both long-period (20–100 s) and short-period (3–20 s) ground motions. In order to reproduce the observed large slip area (slip asperity), we assign a large Dc (slip critical distance) area following kinematic source inversion results. Sufficiently large slip is achieved through rupture reactivation by the double-slip-weakening friction model. In order to reproduce the strong-motion generation areas (SMGAs), we assign short Dc and large stress-drop areas following empirical Green’s function (EGF) simulation results, which indicate that, although more distant from the hypocenter, SMGA1 ruptured earlier than SMGA2 or SMGA3, which are closer to the hypocenter. This observation is confirmed by the backprojection method. In order to reproduce this important feature in dynamic simulation results, we introduce a chain of small high stress-drop patches between the hypocenter and SMGA1. By systematic adjustment of stress drops and Dc, the rupture reproduces the observed sequence and timing of SMGA ruptures and the final slip derived by kinematic models. This model also reproduces the multiseismic wavefront observed from strong ground motion data recorded along the Pacific coast of the Tohoku region. We compare the velocity waveforms recorded at rock sites along the coastline with one-dimensional (1D) synthetic seismograms for periods of 20–100 s. The fit is very good at stations in the northern and central areas of Tohoku. We also perform finite-difference method (FDM) simulations for periods of 3–20 s, and confirm that our dynamic model also reproduces wave envelopes. Overall, we are able to validate the rupture process of the Tohoku earthquake.

The Interpersonal Legacy of Chestnut Lodge

This article addresses the context in which Chestnut Lodge Sanatorium evolved its legendary status. Early years of interpersonal psychoanalysis (1920s–1950s) locate the Washington, DC, and Baltimore areas as crucial contexts, both for the professional support they provided to the beginnings of an interpersonal viewpoint, and for the derisive, dismissive attitudes targeting the early proponents of the interpersonal perspective. Chestnut Lodge and the developing White Institute evolved along parallel organizational lines. The development of a compatible clinical sensibility is noted, conceptually linking those identifying as “interpersonal.” Both organizations (“The Lodge” and “White”) share a common intellectual ancestry and a comparable approach to clinical technique. Likewise, both organizations share an emphasis on rejecting dogma and managing to resist organizational pressures in favor of nonconformity and defiance of rigidity. Both organizations are shaped by theorists who are drawn to work intensively with “difficult” patients, as well as with facing powerful personal and political challenges and credible threats of professional exclusion.

A 28-Year History of HIV-1 Drug Resistance and Transmission in Washington, DC.

Washington, DC consistently has one of the highest annual rates of new HIV-1 diagnoses in the United States over the last 10 years. To guide intervention and prevention strategies to combat DC HIV infection, it is helpful to understand HIV transmission dynamics in a historical context. Toward this aim, we conducted a retrospective study (years 1987–2015) of 3,349 HIV pol sequences (1,026 bp) from 1,995 individuals living in the DC area belonging to three different cohorts. We coupled HIV sequence data with clinical information (sex, risk factor, race/ethnicity, viral load, subtype, anti-retroviral regimen) to identify circulating drug resistant mutations (DRM) and transmission clusters and assess their persistence over time. Of the transmission clusters identified in the DC area, 78.0 and 31.7% involved MSM and heterosexuals, respectively. The longest spread of time for a single cluster was 5 years (2007–2012) using a distance-based network inference approach and 27 years (1987–2014) using a maximum likelihood phylogenetic approach. We found eight subtypes and nine recombinants. Genetic diversity increased steadily over time with a slight peak in 2009 and remained constant thereafter until 2015. Nucleotide diversity also increased over time while relative genetic diversity (BEAST) remained relatively steady over the last 28 years with slight increases since 2000 in subtypes B and C. Sequences from individuals on drug therapy contained the highest total number of DRMs (1,104–1,600) and unique DRMs (63–97) and the highest proportion (>20%) of resistant individuals. Heterosexuals (43.94%), MSM (40.13%), and unknown (44.26%) risk factors showed similar prevalence of DRMs, while injection drug users had a lower prevalence (33.33%). Finally, there was a 60% spike in the number of codons with DRMs between 2007 and 2010. Past patterns of HIV transmission and DRM accumulation over time described here will help to predict future efficacy of ART drugs based on DRMs persisting over time and identify risk groups of interest for prevention and intervention efforts within the DC population. Our results show how longitudinal data can help to understand the temporal dynamics of HIV-1 at the local level.

Abstract P115: Prevalence of Undiagnosed Diabetes Decreases by Eighty Percent When A1C Replaces the OGTT: The Africans in America Study

Introduction: Africa has the highest prevalence of undiagnosed diabetes (DM) in the world. It is unknown whether programs designed to screen for DM in Africa should rely on hemoglobin A 1C (A1C) or the 2h oral glucose tolerance test (OGTT). In general, the prevalence of undiagnosed DM is lower when detection is based on A1C rather than the OGTT. However, the degree to which the prevalence of undiagnosed DM would be lower in Africans if A1C rather than the OGTT was used is unknown. Heterozygous hemoglobinopathies such as sickle cell trait (SCT) and hemoglobin C (HbC) trait may lower A1C independent of the degree of glycemia, potentially compromising the ability of A1C to detect DM. Objective: Our goals were to determine in Africans the rate of detection and reproducibility of the diagnosis of DM by both A1C and OGTT. Methods: Ninety African-born blacks (66% (59/90) male, age 40±11y (mean±SD), BMI 27.6±4.6 kg/m 2 ) who self-identified as healthy, currently live in the Washington DC area and enrolled in the Africans in America study had two OGTT performed 10±8 days apart. At both visits A1C was assayed by HPLC from whole blood and glucose from plasma samples taken at -15, 0, 30, 60, 90 and 120 minutes. For A1C, DM was diagnosed by levels ≥6.5%. For the OGTT, fasting glucose ≥126 mg/dL or 2h glucose≥200 mg/dL was required to diagnose DM. The κ-statistic was used to evaluate reproducibility. Hemoglobin electrophoresis was performed. Results: At Visit 1: DM was diagnosed by A1C in 4% (4/90) and by OGTT in 26% (23/90). At Visit 2: DM was diagnosed by A1C in 3% (3/89) and by OGTT in 21% (19/90). Diagnosis by A1C and OGTT displayed substantial (κ=0.74) and almost perfect (κ=0.88) reproducibility, respectively. All persons with DM diagnosed by A1C criteria at either visit were also diagnosed by OGTT. However, 83% (19/23) of people with DM diagnosed by OGTT were not detected by A1C. In the entire cohort the combined prevalence of HbS and HbC trait was 14% (13/90). However, the prevalence of SCT and HbC trait in people with DM diagnosed by OGTT was 42% (8/19), but no one with SCT or HbC trait had an A1C level≥6.5%. Conclusion: Diagnosis of DM by both A1C and OGTT are highly reproducible in African immigrants. However, A1C detects 80% fewer people with DM than does the glucose criteria for the OGTT. The clinical consequences of this lower rate of detection of DM by A1C remains to be determined in prospective studies.

Abstract P116: The Oral Glucose Tolerance Test is Highly Reproducible for the Diagnosis of Diabetes in Africans: The Africans in America Study

Introduction: As the diabetes epidemic spreads across Africa, the oral glucose tolerance test (OGTT) has the potential to provide important information on glucose tolerance category for the individual and across the population. However, for both patient care and the collection of prevalence statistics, there needs to be a high degree of certainty that the diagnosis made by a single OGTT is reproducible. There are no rigorous studies on the reproducibility of the OGTT in Africans. Objective: By performing two OGTT in African-born blacks living in the Washington DC area, our goal was to evaluate the reproducibility of: a) the glucose tolerance category b) time to glucose peak, c) shape of glucose curve, d) glucose concentration at 60 minutes. Methods: The participants were 90 African-born blacks (66% male (59/90), age 40±11y (mean±SD), BMI 27.6±4.6 kg/m 2 ), who self-identified as healthy and were enrolled in the Africans in America cohort. Two OGTT were performed 10±8 days apart. At each OGTT plasma samples were taken at -15, 0, 30, 60, 90 and 120 minutes. Diabetes (DM), prediabetes (pre-DM) and normal glucose tolerance (NGT)was defined by ADA guidelines for glucose. The shape of the glucose curve was characterized as monophasic, biphasic or indeterminate. During the OGTT, glucose at 60 minutes ≥ 155 mg/dL was defined as elevated. The κ-statistic was used to evaluate reproducibility (slight 0.00 to 0.20, fair 0.21 to 0.40; substantial 0.61 to 0.80, excellent 0.81 to 1.0). Results: At OGTT-1, DM, pre-DM and NGT occurred in 26% (23/90), 27% (24/90) and 48% (43/90), resp. At OGTT-2, DM, pre-DM and NGT occurred in 21% (19/90), 28% (25/90) and 51% (46/90) resp. Reproducibility for the diagnosis of glucose tolerance status (NGT, pre-DM, or DM) was just substantial (κ=0.66). However, reproducibility for the diagnosis of diabetes (DM or no DM) was excellent (κ=0.88). Furthermore, no one without DM at OGTT-1 was identified as having DM at OGTT-2. The reproducibility of time to glucose peak was only fair (κ=0.32), but 100% of participants with DM had peak glucose after 30 min. Similarly, the shape of the glucose curve had fair reproducibility (κ=0.21), but no one with DM had a biphasic curve. For elevated 60 min glucose, reproducibility was substantial (κ=0.62) and 96% (22/23) of the participants with DM had elevated glucose at 60 min. Conclusion: When duplicate OGTT were performed in Africans, the diagnosis of DM and the morphology of the glucose curves were highly reproducible.

Travel behavior and price preferences of bikesharing members and casual users: A Capital Bikeshare perspective

Even though casual users of bikeshare account for a large share of ridership and revenue at public bikeshare systems in North America, very little is known about the characteristics and preferences of casual users and how they compare to registered members. The primary objectives of the study include identifying the similarities and differences between members and casual users along demographics, usage and indicated preferences; and examining and modeling pricing preferences of bikeshare users. An intercept survey was conducted to obtain demographic information, bikeshare usage and various preferences of Capital Bikeshare users in the metro Washington DC area. The survey data was validated against the data from an existing member survey with large sample using goodness of fit tests. Survey participants reported that single trip fare (STF) and annual membership paid at once as their preferred pricing options and a combination of STF, 24-hour pass, and annual membership with monthly installments as their favorable pricing model. Logistic regression findings indicate that, when compared to casual users, registered members are more likely to be White, earn more and reside in the D.C. area. Casual users make fewer bikeshare trips and are less sensitive to the service (station density) compared to members. Gender, age and income distribution do not appear to influence casual fare product choice. Results from this study are useful in policy-making, planning and operations for bikeshare systems.

Using graphic text-messaging to promote smoking cessation among first-generation Chinese and Korean male immigrants.

First-generation Chinese and Korean male immigrants in the United States are at high risk for tobacco use. This study pilot-tested a graphic, native-language text-messaging intervention to promote smoking cessation among these groups. First-generation Chinese and Korean male immigrant smokers (N = 71) were recruited from the Washington DC area. Participants were randomly assigned to one of four conditions based on a between-subjects 2 (graphic plus text or text-only messages) � 2 (quitline information or quitting tips) design. The text-messaging intervention included 30 text messages in total and lasted one month. Participants completed an expired air carbon monoxide (CO) assessment and self-reported measures at both baseline and follow-up. Results show that, from baseline to follow-up, participants' expired air CO levels decreased significantly (P = 0.001). Attitude toward quitting also became more positive (P = 0.028). Compared with text-only messages, graphic text messages produced greater positive changes in quitting attitudes (P = 0.039) and elicited greater fear response (P = 0.005). Compared with quitting tip messages, quitline information resulted in greater regret (P = 0.016) and fear (P = 0.051). These findings suggest that graphic text-messaging can be an effective method to promote smoking cessation among first-generation Chinese and Korean male immigrants.

Plaque features in saphenous vein graft evaluated by virtual histology intravascular ultrasound

Objective: To investigate the features of plaques of saphenous venous graft (SVG) with virtual histology intravascular ultrasound (VH-IVUS) in patients underwent coronary artery bypass graft surgery. Methods: From March 2016 to March 2018, a total of 45 patients ((64.4±7.9) years old, 88.9% male (40 cases)) with ischemic symptoms after coronary artery bypass graft surgery and with coronary artery angiography evidenced SVG stenosis greater than or equal to 50%, who received percutaneous coronary intervention in Tianjin chest hospital were continuously included in this study, and the clinical data were retrospectively analyzed. VH-IVUS was performed before PCI to analyze plaque composition. The patients were divided into no smoking group (21 cases) and smoking group (24 cases), no diabetes group (30 cases) and diabetes group (15 cases), normal very low density lipoprotein cholesterin (VLDL-C) group (24 cases) and elevated VLDL-C group (21 cases), stable angina pectoris group (5 cases) and acute coronary syndrome group (40 cases), plaque burden (PB) < 70% group (11 cases) and PB ≥ 70% group (34 cases), without thin-cap fibroatheroma group (35 cases) and thin-cap fibroatheroma group (10 cases), and plaque features were compared between different groups. Results: The graft age was (8.9±3.7) years.The stenosis degree of SVG lesions was 90 (90, 98) %. The minimum lumen diameter was 1.6 (1.5, 1.8) mm. The vessel cross-sectional area was (12.1±4.0) mm(2). The plaque area was 8.6 (5.7,12.0) mm(2). The minimum lumen area was 2.5 (2.1,3.3) mm(2). The plaque burden was (75.3±8.3)%. The fibrotic tissue (FI) ratio was (65.1±10.1)%, fibrofatty plaque (FF) ratio was 13.8 (5.4,25.3) %, necrotic core tissue (NC) ratio was 12.0 (5.4,24.0)%, and dense calcium tissue (DC) ratio was1.0 (0.2,3.8)% in SVG lesions. There were no significant differences in SVG plaque area, FI area,FF area,NC area,and DC area between no smoking group and smoking group, no diabetes group and diabetes group, and normal VLDL-C group and elevated VLDL-C group. SVG plaque volume was significantly higher in acute coronary syndrome group than in stable angina pectoris group (262.2 (148.5,401.2) mm(3) vs. 93.1 (50.6,155.9) mm(3),P=0.006), and plaque area (10.1 (6.6,13.3) mm(2) vs. 5.0 (3.6,6.9) mm(2), P<0.001), FI area(4.8 (3.2,6.8) mm(2) vs. 2.8 (1.9,3.0) mm(2), P<0.001),and FF area (1.15 (0.60, 2.07) mm(2) vs. 0.30 (0.10,0.90) mm(2), P=0.009) were significantly larger in PB ≥ 70% group than in PB < 70% group.The NC area (1.75(0.40,2.78) mm(2) vs. 0.60 (0.20,1.30) mm(2), P=0.030) and DC area (0.35 (0.10,0.50) mm(2) vs. 0.00 (0.00,0.10) mm(2), P=0.006) were significantly larger in thin-cap fibroatheroma group than that in without thin-cap fibroatheroma group. Spearman correlation analysis showed that the plaque area of SVG lesion was positively correlated with FF area (r=0.64, P<0.001) and NC area (r=0.43, P=0.003). PB was positively correlated with FF area (r=0.50, P<0.001) and NC area (r=0.33, P=0.028). Graft age was positively correlated with FF area (r=0.30, P=0.047). Conclusions: The main components of SVG plaque are fibrotic tissue, conversely, calcified tissue is rare in patients with SVG stenosis after coronary artery bypass graft surgery. Fibrofatty tissue is increased in the plaque in patients with PB ≥ 70%. The necrotic component is also increased in patients with thin-cap fibroatheroma. The fibrofatty component increases and the plaque tends to be unstable in proportion with increaing age of the graft in this patient cohort.

Active Shooter and Terrorist Event-Related Posttraumatic Stress and Depression: Television Viewing and Perceived Safety.

This study examined the relationship of sniper-related television viewing (TV) and perceived safety to posttraumatic stress (PTS) and depressive symptoms during the Washington, DC sniper attacks. Participants were 1238 Washington, DC area residents assessed using an internet survey including the Impact of Event Scale-Revised, Patient Health Questionnaire-9, hours of TV, and perceived safety. Almost 40% (n = 459) of participants watched at least 2 hours of sniper-related TV daily. TV viewing was associated with lower total perceived safety. After adjusting for demographics, more TV viewing and decreased perceived safety were related to increased PTS and depressive symptoms. TV viewing modified the effect of safety on PTS and depressive symptoms. Among participants with low and high perceived safety, hours of TV were positively associated with PTS; however, the effect was stronger among those with low perceived safety. The relationship of TV to increased depressive symptoms was identified only in participants who reported low perceived safety. The influence of media exposure and perceived safety have implications for intervention by community leaders and mental health care providers. Recommendations include limiting media exposure during a terrorist event, particularly among those who perceive that their safety is at risk, and targeting safety in communication strategies. (Disaster Med Public Health Preparedness. 2019;13:570-576).

Redesign of a Service-learning Social Entrepreneurship Program for High School Students Part I

Started as a program in 2003 and then incorporated as a nonprofit in 2008, each year, LearnServe has taken students of diverse backgrounds from the Washington, DC area to experience a summer of international service-learning and social entrepreneurship. However, the students who travel abroad are not always prepared to go or able to successfully complete the post-trip activities. With experiences of extreme homesickness and severe culture shock, a lack of true social empowerment projects during the trip, and a lack of engagement in social entrepreneurship after the trip, the program directors realized there was a need to improve the LearnServe curriculum. The aim was to create an improved educational experience that prepares students to travel, engages them during the trip, and creates sharing and entrepreneurial opportunities afterwards. This paper presents the design research and prototyping work completed to redesign this service-learning program so that it meets its goals for success, more effectively preparing students to have a successful service-learning trip abroad and engaging social entrepreneurship work upon return.

Newcomer Central American Immigrants' Access to Legal Services

Increased Central American child and family migration is impacting local communities across the U.S. Between late 2013 and mid 2018, over 193,000 unaccompanied children (UACs) and 300,000 adults and children traveling as family units from Central America were apprehended at the U.S.-Mexico border. As their cases overburden the immigration courts, federal engagement in the provision of immigration legal services remains virtually non-existent. Local governments and community-based organizations (CBOs) have been forced to improvise how best to provide legal services for this growing newcomer population as they navigate the immigration process. Varying levels of capacity and response across diverse community contexts, however, are contributing to disparities in newcomers’ ability to secure an attorney. Without legal representation, many newcomers face nearly certain deportation regardless of whether they may qualify for immigration relief. To better understand local variations in the provision of legal assistance and barriers faced by Central American migrants in accessing existing services, researchers from the Center for Latin American & Latino Studies (CLALS) at American University and the Graduate College of Social Work at the University of Houston conducted interviews with service providers, local government officials, and other stakeholders across three major immigrant receiving communities: the Washington, DC and Houston metropolitan areas, and North and South Carolina. Drawing on project interviews and publicly available data, this report documents legal service gaps, catalogues the principal challenges confronting community-based legal service providers, and highlights strategies for enhancing service provider capacity and overcoming access barriers. While both public and private partners across a number of U.S communities are engaged in innovative, scaled-up approaches to providing legal services, demand continues to outstrip available resources. The need is particularly acute in localities outside of the major metropolitan areas that are home to large Central American immigrant communities. Significant barriers to access remain and—in the current context of immigration enforcement policy—are accumulating. The forecast of continued strain on an already over-taxed ecology of service providers and on the immigration adjudication system threatens the well-being of tens of thousands of newcomers whose futures hinge on improved capabilities.

Climate of the weakly-forced yet high-impact convective storms throughout the Ohio River Valley and Mid-Atlantic United States

The 1-in-1000-year precipitation event in late June 2016 over West Virginia caused tremendous flooding damage. Like the 2012 mid-Atlantic derecho that blacked out much of the DC area, similar events can be traced to small, mid-tropospheric perturbations (MPs) embedded in the large-scale ridge pattern. Under this “weakly-forced” pattern, severe weather outbreaks commonly occur alongside eastward propagating MPs acting as a triggering mechanism for progressive mesoscale convective systems, which move across the central and eastern US. Forecasting of such weakly-forced yet severe weather events is difficult in both weather and climate timescales. The present diagnostic analysis of the MP climatology is the first step toward developing metrics that can identify and evaluate weakly-forced severe weather outbreaks in multi-model projections. We report a discernable, potentially pronounced subseasonal change in the MP climatology associated with the changing climate of North America. Both sea surface temperatures within the Gulf of Mexico and mid-level high pressure over the central US were found to exhibit strong correlations with MPs. Analysis of regional climate downscaling indicates a projected increase in MP frequency and the associated convective precipitation through the mid twenty-first century.