• MgB2 ultrathin films fabricated by hybrid physical chemical vapor deposition and ion milling

      Acharya, Narendra; Wolak, Matthäus A.; Tan, Teng; Lee, Namhoon; Lang, Andrew C.; Taheri, Mitra; Cunnane, Dan; Karasik, Boris S.; Xi, X. X.; 0000-0003-2297-2321 (2016-08-29)
      In this letter, we report on the structural and transport measurements of ultrathin MgB2 films grown by hybrid physical-chemical vapor deposition followed by low incident angle Ar ion milling. The ultrathin films as thin as 1.8 nm, or 6 unit cells, exhibit excellent superconducting properties such as high critical temperature (Tc) and high critical current density (Jc). The results show the great potential of these ultrathin films for superconducting devices and present a possibility to explore superconductivity in MgB2 at the 2D limit.
    • Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient

      Tan, Teng; Wolak, Matthäus A.; Xi, X. X.; Tajima, T.; Civale, L. (2016-10-24)
      Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (Hvp). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases Hvp. In this work, we utilized Nb ellipsoid to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of Hvp was observed. At 2.8K, Hvp increased from 2100Oe for an uncoated Nb ellipsoid to 2700Oe for a Nb ellipsoid coated with ~200nm thick MgB2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.
    • Essential or Expendable Supports? Assessing the Relationship between School Climate and Student Outcomes

      Sørensen, Jesper; Morgan, Stephen (2017-01-10)
      Sociologists of education argue that school organizational practices and climates influence students’ academic outcomes. The predominant measure of school climates are aggregated student and teacher survey reports, which are diffusing into official educational statistics. Unfortunately, most studies are unable to rigorously assess the causal effects of these measures of school organization. This study does so by examining the effects of school climate experienced in grades 4–8 by different cohorts of students in Chicago Public Schools (CPS). Improvement in school climates has small positive associations with students’ eighth grade test scores and null to minimal associations with students’ chances of on-time ninth grade promotion and high school graduation.
    • Reward and punishment sensitivity and disordered eating behaviors in men and women

      Eneva, Kalina T.; Murray, Susan; O’Garro-Moore, Jared; Yiu, Angelina; Alloy, Lauren B.; Avena, Nicole M.; Chen, Eunice; 0000-0002-9288-7133 (2017-02-16)
      Background: Reward and punishment sensitivities have been identified as potential contributors to binge eating and compensatory behaviors, though few studies have examined gender differences in these behaviors. Method: A college-aged sample (N = 1,022) completed both the Eating Disorders Diagnostic Scale (EDDS) and Sensitivity to Punishment/Sensitivity to Reward Questionnaire (SPSRQ). Results: Rates of binge eating were similar in males and females. Among those reporting compensatory behaviors, women reported engaging in compensatory behaviors more frequently than men. Sensitivity to reward and sensitivity to punishment were both positively associated with binge eating frequency in both genders. In contrast, women with high reward sensitivity reported engaging in compensatory behaviors more frequently. Conclusions: Rates of binge eating and compensatory weight control behaviors were similar between college-aged males and females, though females who engaged in compensatory behaviors did so more frequently than males. Sensitivity to punishment was greater in females, whereas sensitivity to reward was greater in males. Reward and punishment sensitivity were each positively associated with binge eating in both males and females, while only reward sensitivity was positively associated with compensatory behaviors in females.
    • Chromatin dynamics during the differentiation of long-term hematopoietic stem cells to multipotent progenitors

      Yu, Xiang Yu; Wu, Chao; Bhavanasi, Dheeraj; Wang, Hong; Gregory, Brian D.; huang, Jian; 0000-0002-1649-0038 (2017-05-30)
    • A Rare Case of Aortoatrial Fistula from Streptococcal Endocarditis

      Arshad, Hammad; Young, Meilin; Rali, Parth (2017-07-05)
      We represent an unfortunate case of postinfluenza streptococcal endocarditis in a 34-year-old healthy male. He presented with hypoxic respiratory failure and was found to have mitral and aortic valve vegetation. Hospital course was complicated by the presence of an aortoatrial fistula from an aortic root abscess, persistent septic shock, and multiorgan failure.
    • Area-based socioeconomic factors and Human Papillomavirus (HPV) vaccination among teen boys in the United States

      Swiecki-Sikora, Allison L.; Stroup, Antoinette M.; Warner, Echo L.; Kepka, Deanna; Henry, Kevin; 0000-0002-5348-9669 (2017-07-14)
      Background: This study is the first to examine associations between several area-based socioeconomic factors and human papillomavirus (HPV) vaccine uptake among boys in the United States (U.S.). Methods: Data from the 2012-2013 National Immunization Survey-Teen restricted-use data were analyzed to examine associations of HPV vaccination initiation (receipt of ≥1 dose) and series completion (receipt of three doses) among boys aged 13-17 years (N = 19,518) with several individual-level and ZIP Code Tabulation Area (ZCTA) census measures. Multivariable logistic regression was used to estimate the odds of HPV vaccination initiation and series completion separately. Results: In 2012-2013 approximately 27.9% (95% CI 26.6%-29.2%) of boys initiated and 10.38% (95% CI 9.48%-11.29%) completed the HPV vaccine series. Area-based poverty was not statistically significantly associated with HPV vaccination initiation. It was, however, associated with series completion, with boys living in high-poverty areas (≥20% of residents living below poverty) having higher odds of completing the series (AOR 1.22, 95% CI 1.01-1.48) than boys in low-poverty areas (0-4.99%). Interactions between race/ethnicity and ZIP code-level poverty indicated that Hispanic boys living in high-poverty areas had a statistically significantly higher odds of HPV vaccine initiation (AOR 1.43, 95% CI 1.03-1.97) and series completion (AOR 1.56, 95% CI 1.05-2.32) than Hispanic boys in low-poverty areas. Non-Hispanic Black boys in high poverty areas had higher odds of initiation (AOR 2.23, 95% CI 1.33-3.75) and completion (AOR 2.61, 95% CI 1.06-6.44) than non-Hispanic Black boys in low-poverty areas. Rural/urban residence and population density were also significant factors, with boys from urban or densely populated areas having higher odds of initiation and completion compared to boys living in non-urban, less densely populated areas. Conclusion: Higher HPV vaccination coverage in urban areas and among racial/ethnic minorities in areas with high poverty may be attributable to factors such as vaccine acceptance, health-care practices, and their access to HPV vaccines through the Vaccines for Children Program, which provides free vaccines to uninsured and under-insured children. Given the low HPV vaccination rates among boys in the U.S., these results provide important evidence to inform public health interventions to increase HPV vaccination.
    • Transverse Thermoelectricity in Fibrous Composite Materials

      Qian, Bosen; Ren, Fei; 0000-0002-8868-4536 (2017-07-16)
      Transverse thermoelectric elements have the potential to decouple the electric current and the heat flow, which could lead to new designs of thermoelectric devices. While many theoretical and experimental studies of transverse thermoelectricity have focused on layered structures, this work examines composite materials with aligned fibrous inclusions. A simplified mathematical model was derived based on the Kirchhoff Circuit Laws (KCL), which were used to calculate the equivalent transport properties of the composite structures. These equivalent properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity, compared well with finite element analysis (FEA) results. Peltier cooling performance was also examined using FEA, which exhibited good agreement to KCL model predictions. In addition, a survey was conducted on selected combinations of thermoelectric materials and metals to rank their transverse thermoelectricity with respect to the dimensionless figure of merit.
    • Intraoperative Techniques for the Plastic Surgeon to Improve Pain Control in Breast Surgery

      Farias-Eisner, Gina; Kao, Kenneth; Pan, Judy; Festekjian, Jaco; Gassman, Andrew (2017-11-15)
      In recent years, there has been a growing emphasis placed on reducing length of hospital stay and health costs associated with breast surgery. Adequate pain control is an essential component of enhanced recovery after surgery. Postoperative pain management strategies include use of narcotic analgesia, non-narcotic analgesia, and local anesthetics. However, these forms of pain control have relatively brief durations of action and multiple-associated side effects. Intraoperative regional blocks have been effectively utilized in other areas of surgery but have been understudied in breast surgery. The aim of this article was to review various intraoperative techniques for regional anesthesia and local pain control in breast surgery and to highlight areas of future technique development.
    • Tunable two-dimensional interfacial coupling in molecular heterostructures

      Xu, Beibei; Chakraborty, Himanshu; YADAV, VIVEK; zhang, zhuolei; Klein, Michael L.; Ren, Shenqiang; 0000-0002-9142-4567; 0000-0003-0207-3038 (2017-11-17)
      Two-dimensional van der Waals heterostructures are of considerable interest for the next generation nanoelectronics because of their unique interlayer coupling and optoelectronic properties. Here, we report a modified Langmuir–Blodgett method to organize two-dimensional molecular charge transfer crystals into arbitrarily and vertically stacked heterostructures, consisting of bis(ethylenedithio)tetrathiafulvalene (BEDT–TTF)/C60 and poly(3-dodecylthiophene-2,5-diyl) (P3DDT)/C60 nanosheets. A strong and anisotropic interfacial coupling between the charge transfer pairs is demonstrated. The van der Waals heterostructures exhibit pressure dependent sensitivity with a high piezoresistance coefficient of −4.4 × 10−6 Pa−1, and conductance and capacitance tunable by external stimuli (ferroelectric field and magnetic field). Density functional theory calculations confirm charge transfer between the n-orbitals of the S atoms in BEDT–TTF of the BEDT–TTF/C60 layer and the π* orbitals of C atoms in C60 of the P3DDT/C60 layer contribute to the inter-complex CT. The two-dimensional molecular van der Waals heterostructures with tunable optical–electronic–magnetic coupling properties are promising for flexible electronic applications.
    • Meeting Students Halfway: Increasing Self-Efficacy and Promoting Knowledge Change in Astronomy

      Bailey, Janelle; Lombardi, Doug; Cordova, Jacqueline R.; Sinatra, Gale M.; 0000-0001-9563-2016 (2017-12-26)
      Two motivational factors--self-efficacy and interest--may be especially relevant to deepening students' understanding of astronomy. We examined the relationship between students' self-efficacy for, interest in learning about, and changes in their knowledge of stars, as measured by the Star Properties Concept Inventory (SPCI). Approximately 700 undergraduate students taking introductory astronomy responded to surveys at the start and end of their semester-long course. A sequential multiple regression analysis showed that self-efficacy post explains an appreciable percentage of variance in SPCI posttest scores, more than twice the percentage explained by all the pretest variables (SPCI, self-efficacy, and interest) combined. Knowledge and self-efficacy improved significantly over instruction; interest did not. Follow-up analyses revealed that instructors whose classes increased in self-efficacy also had the greatest increases in knowledge scores. Interviews with these instructors suggest they provide their students with more opportunities for mastery experiences with elaborated, performance-related feedback, as well as strong positive verbal persuasion and vicarious experiences through peer instruction. Through increased understanding of the relationship between motivational constructs (e.g., self-efficacy, interest) and knowledge, we can both improve our models and better inform instruction.
    • Krüppel-Like Factors: Crippling and Uncrippling Metabolic Pathways

      Metabolic Biology Laboratory, Center for Translational Medicine (2018-02-01)
      Krüppel-like factors (KLFs) are deoxyribonucleic acid–binding transcriptional factors that regulate various pathways that control metabolism and other cellular mechanisms. Various KLF isoforms have been associated with cellular, organ, or systemic metabolism. Altered expression or activation of KLFs has been linked to metabolic abnormalities, such as obesity and diabetes, as well as with heart failure. This review article summarizes the metabolic functions of KLFs, as well as the networks of different KLF isoforms that jointly regulate metabolism in health and disease.
    • Is non-invasive indocyanine-green angiography a useful adjunct for the debridement of infected sternal wounds?

      Tyrell, Richard O.; Kilmartin, Catherine; Acevedo, Edwin; Keshavamurthy, Suresh; Gassman, Andrew; 0000-0002-5578-1911 (2018-05-01)
      Laser-assisted indocyanine-green imaging (ICG) has a wide range of surgical applications, and has been used in reconstructive surgery to aid in assessing the viability of free tissue transfers and to help predict poor tissue perfusion. However, its indications for use is limited to assessing free flap tissue perfusion, coronary artery perfusion during coronary artery bypass (CABG), and tissue perfusion in diabetic foot ulcers, to name a few. This system has been proven to be a safe, reliable adjunctive modality to assess microvascular compromise or poor perfusion peri-operatively, which could minimize skin necrosis and other post-operative complications (Further et al., 2013).1 The ability to objectively assess tissue perfusion has led to improved post-operative outcomes in breast, abdominal wall, colorectal, and cardiac surgery. To date, no studies have reviewed the use of ICG in delineating devitalized bone during sternal wound debridement after cardiac surgery. At our institution, we have encountered a cohort of patients with post-cardiac surgery sternal wound infections who have required debridement of infected and devitalized bone. We propose that SPY technology aids in delineating this devitalized bone, and may aid in the timing muscle flap coverage. In this paper, we will demonstrate two cases of patients who had post-operative sternal wound infections after undergoing cardiac surgery for which ICG was used to demarcate debridement zones and subsequent flap coverage. In these cases, ICG allowed for efficient and reliable intraoperative evaluation of bony perfusion and has aided in early adequate debridement and flap coverage.
    • Nature of the metal-insulator transition in few-unit-cell-thick LaNiO3 films

      Golalikhani, M.; Lei, Q.; Chandrasena, Ravini; Kasaei, L.; Park, H.; Bai, J.; Orgiani, P.; Ciston, J.; Sterbinsky, G. E.; Arena, D. A.; Shafer, P.; Arenholz, E.; Davidson, Bruce; Millis, A. J.; Gray, A. X.; Xi, X. X.; 0000-0001-8766-0965; 0000-0003-1616-9380 (2018-05-07)
      The nature of the metal-insulator transition in thin films and superlattices of LaNiO3 only a few unit cells in thickness remains elusive despite tremendous effort. Quantum confinement and epitaxial strain have been evoked as the mechanisms, although other factors such as growth-induced disorder, cation non-stoichiometry, oxygen vacancies, and substrate–film interface quality may also affect the observable properties of ultrathin films. Here we report results obtained for near-ideal LaNiO3 films with different thicknesses and terminations grown by atomic layer-by-layer laser molecular beam epitaxy on LaAlO3 substrates. We find that the room-temperature metallic behavior persists until the film thickness is reduced to an unprecedentedly small 1.5 unit cells (NiO2 termination). Electronic structure measurements using X-ray absorption spectroscopy and first-principles calculation suggest that oxygen vacancies existing in the films also contribute to the metal-insulator transition.
    • A Novel Cell Penetrating Peptide for the Differentiation of Human Neural Stem Cells

      Ma, Weili; Jin, Geun-woo; Gehret, Paul M.; Chada, Neil C.; Suh, Won H.; 0000-0002-4036-8307 (2018-07-09)
      Retinoic acid (RA) is a bioactive lipid that has been shown to promote neural stem cell differentiation. However, the highly hydrophobic molecule needs to first solubilize and translocate across the cell membrane in order to exert a biological response. The cell entry of RA can be aided by cell penetrating peptides (CPPs), which are short amino acid sequences that are able to carry bioactive cargo past the cell membrane. In this work, a novel cell penetrating peptide was developed to deliver RA to human neural stem cells and, subsequently, promote neuronal differentiation. The novel CPP consists of a repeating sequence, whose number of repeats is proportional to the efficiency of cell penetration. Using fluorescence microscopy, the mode of translocation was determined to be related to an endocytic pathway. The levels of β-III tubulin (Tubb3) and microtubule associated protein 2 (MAP2) expression in neural stem cells treated with RA conjugated to the CPP were assessed by quantitative immunocytochemistry.
    • MgB2 Josephson junctions produced by focused helium ion beam irradiation

      Temple Materials Institute (2018-07-19)
      Planar magnesium diboride Josephson junctions are fabricated using focused helium ion beam irradiation. A single track of ion irradiation with a 30 kV He+ beam with nominal beam diameter < 0.5 nm is used to create a normal-metal barrier on a MgB2 film deposited by hybrid physical-chemical vapor deposition. Josephson coupling is observed below the critical temperature of the electrodes for a He+ doses between 8x1015/cm2 to 4x1016/cm2 . Analysis of the temperature dependence of the normal resistance and critical voltage of the junctions shows highly uniform barriers with nearly ideal resistively-shunted junction behavior for higher-dose junctions, while nonequilibrium effects dominate the properties of lower-dose junctions over most of the temperature range. These results demonstrate that focused helium ion beam irradiation can produce high-quality proximity-coupled MgB2 Josephson junctions with tailorable properties, promising for use in superconducting devices and circuits.
    • Is Parent–Child Disagreement on Child Anxiety Explained by Differences in Measurement Properties? An Examination of Measurement Invariance Across Informants and Time

      Innamorati, Marco (2018-07-31)
      There are numerous empirical studies demonstrating that agreement between parent-reports of youth and youth self-reports of internalizing behavior problems is modest at best. This has spurred much research on factors that influence the magnitude of associations between informants, including individual difference characteristics of the informants and contexts through which individuals interact with the child. There is also tremendous interest in understanding symptom trajectories longitudinally. However, each of these lines of work are predicated on the assumptions that the psychometric construct that is being assessed from each informant and at each measurement occasion is the same. This study examined measurement invariance between maternal and child reports and longitudinally across ages 9 and 12 on five dimensions of anxiety using the Screen for Child Anxiety and Related Disorders (SCARED; Birmaher et al., 1999). No cross-informant models for anxiety dimensions achieved acceptable fit and at least partial metric and scalar invariance. Moreover, few longitudinal models demonstrated acceptable fit and at least partial metric and scalar invariance. Thus, using the SCARED as an example, these results show that inter-informant agreement may be compromised by different item functioning, and highlight the need for testing invariance before using measures for longitudinal tracking of symptoms.
    • Administration of intravenous antibiotics in patients with open fractures is dependent on emergency room triaging

      Phillips, Cameron (2018-08-14)
      Recent literature has demonstrated that emergent administration of antibiotics is perhaps more critical than even emergent debridement. Most recent studies recommend patients receive antibiotics no later than 1 hour after injury to prevent infection. The objective of this study is to evaluate the time to antibiotic administration after patients with open fractures arrive to a trauma center depending on triaging team.
    • The Effects of Selective Muscle Weakness on Muscle Coordination in the Human Arm

      Zaffagnini, Stefano (2018-09-19)
      Despite the fundamental importance of muscle coordination in daily life, it is currently unclear how muscle coordination adapts when the musculoskeletal system is perturbed. In this study, we quantified the impact of selective muscle weakness on several metrics of muscle coordination. Seven healthy subjects performed 2D and 3D isometric force target matches, while electromyographic (EMG) signals were recorded from 13 elbow and shoulder muscles. Subsequently, muscle weakness was induced by a motor point block of brachialis muscle. Postblock subjects repeated the force generation tasks. We quantified muscle coordination pre- and postblock using three metrics: tuning curve preferred direction, tuning curve area, and motor modules analysis via nonnegative matrix factorization. For most muscles, the tuning direction for the 2D protocol was not substantially altered postblock, while tuning areas changed more drastically. Typically, five motor modules were identified from the 3D task, and four motor modules were identified in the 2D task; this result held across both pre- and postblock conditions. The composition of one or two motor modules, ones that involved mainly the activation of shoulder muscles, was altered postblock. Our results demonstrate that selective muscle weakness can induce nonintuitive alternations in muscle coordination in the mechanically redundant human arm.
    • Neural measures of anticipatory bodily attention in children: Relations with executive function

      Meredith Weiss, Staci; Meltzoff, Andrew N.; Marshall, Peter J. (2018-09-29)
      The ability to selectively direct attention to a certain location or modality is a key neurocognitive skill. One important facet of selective attention is anticipation, a foundational biological construct that bridges basic perceptual processes and higher-order cognition. The current study focuses on the neural correlates of bodily anticipation in 6- to 8-year-old children using a task involving tactile stimulation. Electroencephalographic (EEG) activity over sensorimotor cortex was measured after a visual cue directed children to monitor their right or left hand in anticipation of tactile stimulation. Prior to delivery of the tactile stimulus, a regionally-specific desynchronization of the alpha-range mu rhythm occurred over central electrode sites (C3/C4) contralateral to the cue direction. The magnitude of anticipatory mu rhythm desynchronization was associated with children’s performance on two executive function tasks (Flanker and Card Sort). We suggest that anticipatory mu desynchronization has utility as a specific neural marker of attention focusing in young children, which in turn may be implicated in the development of executive function.