Drexel University
  • Philadelphia, PA, United States
Recent publications
Assessment of expertise development during training program primarily consists of evaluating interactions between task characteristics, performance, and mental load. Such a traditional assessment framework may lack consideration of individual characteristics when evaluating training on complex tasks, such as driving and piloting, where operators are typically required to execute multiple tasks simultaneously. Studies have already identified individual characteristics arising from intrinsic, context, strategy, personality, and preference as common predictors of performance and mental load. Therefore, this study aims to investigate the effect of individual difference in skill acquisition and transfer using an ecologically valid dual task, behavioral, and brain activity measures. Specifically, we implemented a search and surveillance task (scanning and identifying targets) using a high-fidelity training simulator for the unmanned aircraft sensor operator, acquired behavioral measures (scan, not scan, over scan, and adaptive target find scores) using simulator-based analysis module, and measured brain activity changes (oxyhemoglobin and deoxyhemoglobin) from the prefrontal cortex (PFC) using a portable functional near-infrared spectroscopy (fNIRS) sensor array. The experimental protocol recruited 13 novice participants and had them undergo three easy and two hard sessions to investigate skill acquisition and transfer, respectively. Our results from skill acquisition sessions indicated that performance on both tasks did not change when individual differences were not accounted for. However inclusion of individual differences indicated that some individuals improved only their scan performance (Attention-focused group), while others improved only their target find performance (Accuracy-focused group). Brain activity changes during skill acquisition sessions showed that mental load decreased in the right anterior medial PFC (RAMPFC) in both groups regardless of individual differences. However, mental load increased in the left anterior medial PFC (LAMPFC) of Attention-focused group and decreased in the Accuracy-focused group only when individual differences were included. Transfer results showed no changes in performance regardless of grouping based on individual differences; however, mental load increased in RAMPFC of Attention-focused group and left dorsolateral PFC (LDLPFC) of Accuracy-focused group. Efficiency and involvement results suggest that the Attention-focused group prioritized the scan task, while the Accuracy-focused group prioritized the target find task. In conclusion, training on multitasks results in individual differences. These differences may potentially be due to individual preference. Future studies should incorporate individual differences while assessing skill acquisition and transfer during multitask training.
Stanniocalcin 2 (STC2) is a glycoprotein which is expressed in a broad spectrum of tumour cells and tumour tissues derived from human breast, colorectum, stomach, esophagus, prostate, kidney, liver, bone, ovary, lung and so forth. The expression of STC2 is regulated at both transcriptional and post-transcriptional levels; particularly, STC2 is significantly stimulated under various stress conditions like ER stress, hypoxia and nutrient deprivation. Biologically, STC2 facilitates cells dealing with stress conditions and prevents apoptosis. Importantly, STC2 also promotes the development of acquired resistance to chemo- and radio- therapies. In addition, multiple groups have reported that STC2 overexpression promotes cell proliferation, migration and immune response. Therefore, the overexpression of STC2 is positively correlated with tumour growth, invasion, metastasis and patients’ prognosis, highlighting its potential as a biomarker and a therapeutic target. This review focuses on discussing the regulation, biological functions and clinical importance of STC2 in human cancers. Future perspectives in this field will also be discussed.
Introduction There are persistent gaps in screening, identification, and access to care for common mental disorders in Low- and Middle-Income Countries. An initial step towards reducing this gap is identifying the prevalence, co-morbidities, and context of these disorders in different clinical settings and exploring opportunities for intervention. This study evaluates the prevalence and correlates of depression and substance use disorders among adults presenting to the Emergency Department (ED) of a major national hospital in East Africa. Methods This study utilized the World Health Organization's STEPwise Approach to Surveillance (WHO-STEPS) tool and the Patient Health Questionnaire (PHQ-9) to conduct a cross-sectional survey capturing socio-demographic data, tobacco, and alcohol use and rates of depression in a sample of adults presenting to the ED. Bivariate and multivariate analyses were conducted for each outcome of interest and socio-demographics. Results Of 734 respondents, 298 (40.6%) had a PHQ-9 score in the “moderate” to “severe” range indicative of major depressive disorder. About 17% of respondents endorsed current tobacco use while about 30% reported being daily alcohol users. Those with high PHQ-9 score had higher odds of reporting current tobacco use (“severe range” = adjusted odds ratio (aOR) 1.85, 95% CI 1.05, 3.26). Those with a “severe” PHQ-9 scores were 9 times (aOR 2.3-35.3) more likely to be daily drinkers. Conclusions Screening and identification of people with depression and substance use disorders in the ED of a large national hospital in Kenya is feasible. This offers an opportunity for brief intervention and referral to further treatment.
There is growing evidence that longer travel time by private car poses physical and mental risks. Individual-level obesity and diabetes, two of the main public health challenges in low- and middle-income contexts, could be associated to city-level travel times by car. We used individual obesity and diabetes data from national health surveys from individuals in 178 Latin American cities, compiled and harmonized by the SALURBAL project. We calculated city-level travel times by car using the Google Maps Distance Matrix API. We estimated associations between peak hour city-level travel time by car and obesity and diabetes using multilevel logistic regression models, while adjusting for individual characteristics and other city-level covariates. In our study we did not observe a relationship between city-level peak-hour travel time by car and individual obesity and diabetes, as reported in previous research for individual time spent in vehicles in high-income settings. Our results suggest that this relationship may be more complex in Latin America compared to other settings, especially considering that cities in the region are characterized by high degrees of population density and compactness and by a higher prevalence of walking and public transportation use.
Introduction The US experienced a surge in use of e-cigarettes. Smoking women may consider e-cigarettes during pregnancy as an alternative to smoking. E-cigarettes typically contain nicotine, an established cause of reduction in fetal growth in animal studies. Methods This cohort study included 99,201 mothers who delivered live singletons in 2016–2018 from the Pregnancy Risk Assessment Monitoring System. We created exposure categories based on self-reported number of cigarettes smoked per day and vaping frequency and evaluated their associations with preterm birth and small-for-gestational-age (SGA) birth (two established cigarette smoking-related risks). Results Dual users in late pregnancy were a heterogeneous group: 29% lightly smoked and occasionally vaped; 19% lightly smoked and frequently vaped; 36% heavily smoked and occasionally vaped; and 15% heavily smoked and frequently vaped. While dual users who heavily smoked and occasionally vaped had the highest adjusted OR for SGA (3.4, 95% CI 2.0, 5.7), all the dual users had, on average, about twice the odds of having SGA than non-users. While the risks of preterm birth were higher among sole light smokers (adjusted OR 1.3, 95% CI 1.1, 1.5) and sole heavy smokers (adjusted OR 1.5. 95% CI 1.2, 1.8) than non-users, the adjusted odds of preterm birth for dual users were not noticeably higher than those of non-users. Conclusion Relative to non-users, both smoking and vaping during pregnancy appear to increase risk of SGA, but excess risk of preterm birth appears to be primarily attributable to smoking alone. Higher levels of exposure tended to confer more risk.
Phase change materials have wide applications as thermal energy storage systems. Due to the low thermal conductivity of these materials, lots of efforts have been made to increase the thermal conductivity and efficiency of thermal energy storage systems. In this numerical study, convective and radiation heat transfer on a cavity with transparent inner walls have been investigated considering the effects of buoyancy force and viscosity of phase change materials. For this purpose, computational fluid dynamics that have high accuracy in calculations have been used. The considered wall is made of brick, in which the cavity containing phase change materials is included and layers of cement and plaster are placed on the wall. The results indicate that increasing the heat flux increases the effects of convective heat transfer. In addition, by applying radiation effects, the melting process of paraffin materials increases by 31%. Due to the transparency of the inner walls of the cavity, the radiation process occurred surface to surface. Therefore, with increasing amount of molten material, the radiation effects increase, the reason for this is that RT24 material is more transparent in liquid form than solid material. Also, increasing the heat flux from 50 to 100 and 300 (w/m²) increases the speed of the melting process by 19.3% and 27.2%, respectively.
The study of drop dynamic undergoing collision with solid surfaces seems quite necessary due to its practical applications ranging from coating industries to anti-icing and self-cleaning surfaces. Therefore, we experimentally studied the dynamic of impinging drop on water-repellent surfaces for a wide range of drop properties and initial velocities in terms of weber number (We). We considered the maximum spreading diameter to quantify the spreading dynamic. We modified one of the existing energy-balance models to analytically predict the observed maximum spreading diameters. We showed that above a critical We number (roughly 60–80), the maximum spreading diameter of superhydrophobic surfaces starts to deviate from those of hydrophobic surfaces. Therefore, we incorporated an adjusting factor into the energy-balance model to consider the transition from hydrophobicity to superhydrophobicity. Moreover, we developed a machine learning approach to predict the maximum spreading diameter as a function of drop properties and surface characteristics. Using the machine learning approach, it was found that beyond a critical contact angle (CAadv ∼ 150°–160°) the maximum spreading diameter does not depend on the contact angle anymore. Moreover, for low We numbers, the maximum spreading diameter decrease with increasing the contact angle, while for high We numbers they are directly proportional.
Rumor refutation is a common method to control rumors to address potential risks. This paper studies the social media rumor refutation effectiveness lifecycle (SMRREL), focusing on three important characteristics (i.e., lifespan, peak value, and distribution) to provide support for (1) enhancing the persistence and intensity of rumor refutation effectiveness and (2) investigating the changing law of rumor refutation effectiveness. In total, 77,080 comment records, 55,847 forward records, and other pertinent data of 251 rumor refutation microblogs from an official rumor refutation platform are collected to perform analysis. To explore how the lifespan and peak value of SMRREL are influenced by the possible affecting factors, five regressors (i.e., RFRegressor, AdaBoostRegressor, XGBoostRegressor, LGBMRegressor, and CatBoostRegressor) are trained based on the collected data. The XGBoostRegressor shows the best performance, and the results are shown and explained using SHapley Additive exPlanations (SHAP). To investigate the distribution of SMRREL, lifecycle graphs of rumor refutation effectiveness are summarized and divided into three types, i.e., Outburst, Multiple Peaks, and Steep Slope. Finally, based on the results of the SMRREL analysis, corresponding decision-making recommendations are proposed to make better persistence and intensity of rumor refutation effectiveness.
Insufficient motivation and investment in research and development (R&D) will hamper further developing of the new energy vehicle (NEV) industry. In response to this dilemma, the Chinese government has successively issued the subsidy and dual-credit policies. This study aims at exploring the influence mechanism of the policy transition imposed on the R&D strategy evolution in NEV cooperative innovation network, thus constructing a two-level game model accordingly. Specifically, the inversion method is used a posteriori in the first level to address suppliers' optimal R&D investment. Then, the optimal R&D investment and patent data are used in the second level to construct the network game model, thereby analyzing the influences of the policy transition and of network characteristics on suppliers' R&D strategy evolution. Simulation results suggest that within the subsidy reduction stage, suppliers prefer to choose independent R&D strategy. To summarize, the implementation of the dual-credit policy can reduce the heavy dependence of suppliers' technology R&D upon subsidies while increasing the proportion of suppliers choosing cooperative R&D. In the NEV cooperative innovation network, the evolution of suppliers' R&D strategy can be effectively promoted via not only the controlling over the optimal network clustering coefficient but also the influence of the key nodes within.
While the percentage of mature firms with classified boards or dual class shares has declined by more than 40% since 1990, the percentage of IPO firms with these structures has doubled over this period. We test whether IPO firms implement these structures optimally or whether they are utilized to allow managers to protect their private benefits of control. Both shareholder voting patterns and changes in firm types going public suggest that the Agency Hypothesis best explains IPO firm's use of dual class, particularly when there is a large voting-cash flow wedge. In contrast, among firms with high information asymmetry, classified board structures are better explained by the Optimal Governance hypothesis.
Background The Periodic Risk Evaluation (PRE) is a new questionnaire-based tool to identify autistic adults enrolled in Medicaid programs who are at risk for adverse outcomes including mental health and medical conditions, law enforcement interaction, stressful life events, substance use, presence of natural supports, and suboptimal living conditions. The PRE is completed by direct service providers and informs case conceptualization to drive changes in needed supports. Method The PRE was tested in a sample of 674 autistic adults with a mean age of 31 years across a large, northeastern state. A random forest model was developed to predict complex case status using the PRE items. Sensitivity, specificity, positive predictive value, and negative predictive value for different PRE score cutoffs were evaluated as the performance measures of interest. Expert clinical assessment, the gold standard for case status, identified 131 individuals (19.4 %) as complex cases in need of modified services and supports. Results The final PRE model identified complex cases in unseen data with 75.5 % accuracy, 71.9 % sensitivity, 76.3 % specificity, 41.8 % positive predictive value, and 92.0 % negative predictive value. Conclusions The PRE may be a useful tool for triaging service needs and delivery to adults on the spectrum. The use of the PRE in the Medicaid system is critical because Medicaid is among the only insurers available during the transition to and throughout adulthood for autistic individuals. Adequate planning and assessment of risk can assist direct support staff in triaging and mitigating risk to minimize adverse outcomes.
Background Harnessing CD8⁺ T cell responses is being explored to achieve HIV remission. Although HIV-specific CD8⁺ T cells become dysfunctional without treatment, antiretroviral therapy (ART) partially restores their function. However, the extent of this recovery under long-term ART is less understood. Methods We analyzed the differentiation status and function of HIV-specific CD8⁺ T cells after long-term ART initiated in acute or chronic HIV infection ex vivo and upon in vitro recall. Findings ART initiation in any stage of acute HIV infection promoted the persistence of long-lived HIV-specific CD8⁺ T cells with high expansion (P<0·0008) and cytotoxic capacity (P=0·02) after in vitro recall, albeit at low cell number (P=0·003). This superior expansion capacity correlated with stemness (r=0·90, P=0·006), measured by TCF-1 expression, similar to functional HIV-specific CD8⁺ T cells found in spontaneous controllers. Importanly, TCF-1 expression in these cells was associated with longer time to viral rebound ranging from 13 to 48 days after ART interruption (r =0·71, P=0·03). In contrast, ART initiation in chronic HIV infection led to more differentiated HIV-specific CD8⁺ T cells lacking stemness properties and exhibiting residual dysfunction upon recall, with reduced proliferation and cytolytic activity. Interpretation ART initiation in acute HIV infection preserves functional HIV-specific CD8⁺ T cells, albeit at numbers too low to control viral rebound post-ART. HIV remission strategies may need to boost HIV-specific CD8⁺ T cell numbers and induce stem cell-like properties to reverse the residual dysfunction persisting on ART in people treated after acute infection prior to ART release. Funding U.S. National Institutes of Health and U.S. Department of Defense.
The MXene family of two-dimensional transition metal carbides and nitrides already includes ~50 members with distinct numbers of atomic layers, stoichiometric compositions and solid solutions, in-plane or out-of-plane ordering of atoms, and a variety of surface terminations. MXenes have shown properties that make them attractive for applications ranging from energy storage to electronics and medicine. Although this compositional variability allows fine-tuning of the MXene properties, it also creates challenges during the analysis of MXenes because of the presence of multiple light elements (for example, H, C, N, O, and F) in close proximity. Here, we show depth profiling of single particles of MXenes and their parent MAX phases with atomic resolution using ultralow-energy secondary-ion mass spectrometry. We directly detect oxygen in the carbon sublattice, thereby demonstrating the existence of oxycarbide MXenes. We also determine the composition of adjacent surface termination layers and show their interaction with each other. Analysis of the metal sublattice shows that Mo2TiAlC2 MAX exhibits perfect out-of-plane ordering, whereas Cr2TiAlC2 MAX exhibits some intermixing between Cr and Ti in the inner transition metal layer. Our results showcase the capabilities of the developed secondary-ion mass spectrometry technique to probe the composition of layered and two-dimensional materials with monoatomic-layer precision.
The detection of an astrophysical flux of neutrinos in the TeV–PeV energy range by the IceCube Neutrino Observatory has opened new possibilities for the study of extreme cosmic accelerators. The apparent isotropy of the neutrino arrival directions favors an extragalactic origin for this flux, potentially created by a large population of distant sources. Recent evidence for the detection of neutrino emission from extragalactic sources includes the active galaxies TXS 0506+056 and NGC 1068. We here review the current status of the search for the sources of the high-energy neutrino flux, concentrating on its extragalactic contribution. We discuss the implications of these observations for multimessenger studies of cosmic sources and present an outlook for how additional observations by current and future instruments will help address fundamental questions in the emerging field of high-energy neutrino astronomy. Expected final online publication date for the Annual Review of Nuclear and Particle Science, Volume 72 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Wave‐particle resonant interaction is a key process controlling energetic electron flux dynamics in the Earth's radiation belts. All existing radiation belt codes are Fokker‐Planck models relying on the quasi‐linear diffusion theory to describe the impact of wave‐particle interactions. However, in the outer radiation belt, spacecraft often detect waves sufficiently intense to interact resonantly with electrons in the nonlinear regime. In this study, we propose an approach for estimating and including the contribution of such nonlinear resonant interactions into diffusion‐based radiation belt models. We consider electron resonances with whistler‐mode wave‐packets responsible for injected plasma sheet (∼100 keV) electron acceleration to relativistic energies and/or for their precipitation into the atmosphere. Using statistics of chorus wave‐packet amplitudes and sizes (number of wave periods within one packet), we provide a rescaling factor for quasi‐linear diffusion rates, that accounts for the contribution of nonlinear interactions in long‐term electron flux dynamics. Such nonlinear effects may speed up 0.1–1 MeV electron diffusive acceleration by a factor of ×1.5–2 during disturbed periods. We discuss further applications of the proposed approach and the importance of nonlinear resonant interactions for long‐term radiation belt dynamics.
Background Hispanic men have disproportionate rates of overweight and obesity compared with other racial and ethnic subpopulations. However, few weight loss interventions have been developed specifically for this high-risk group. Furthermore, the use of mobile health (mHealth) technologies to support lifestyle behavior changes in weight loss interventions for Hispanic men is largely untested. Objective This single-arm pilot study examined the feasibility and acceptability of integrating mHealth technology into a 12-week gender- and culturally sensitive weight loss intervention (GCSWLI) for Hispanic men with overweight and obesity. Methods A total of 18 Hispanic men (mean age 38, SD 10.9 years; mean BMI 34.3, SD 5.5 kg/m²; 10/18, 56% Spanish monolingual) received a GCSWLI, including weekly in-person individual sessions, a daily calorie goal, and prescription of ≥225 minutes of moderate-intensity physical activity per week. mHealth technology support included tailored SMS text messaging, behavior self-monitoring support using Fitbit Charge 2, and weight tracking using a Fitbit Aria Wi-Fi Smart Scale. Changes in weight from baseline to 12 weeks were estimated using a paired 2-tailed t test. Descriptive analyses characterized the use of Fitbit and smart scales. Semistructured interviews were conducted immediately after intervention to assess the participants’ weight loss experiences and perspectives on mHealth technologies. Results Of 18 participants, 16 (89%) completed the 12-week assessments; the overall attrition rate was 11.1%. The mean weight loss at week 12 was −4.7 kg (95% CI 7.1 to −2.4 kg; P<.001). Participants wore the Fitbit 71.58% (962/1344) of the intervention days and logged their body weight using the smart scale (410/1344, 30.51% of the intervention days). Participants identified barriers to the use of the technology, such as lack of technological literacy and unreliable internet access for the smart scale. Conclusions Although clinically significant weight loss was achieved by integrating mHealth technology into the GCSWLI, adherence to the prescribed use of technology was modest. Addressing barriers to the use of such technologies identified in our work may help to refine an mHealth intervention approach for Hispanic men. Trial Registration ClinicalTrials.gov NCT02783521; https://clinicaltrials.gov/ct2/show/NCT02783521
Background: Variation exists in family-centered rounds (FCR). Objective: We sought to understand patient/family and clinician FCR beliefs/attitudes and practices to support implementation efforts. Designs, settings and participants: Patients/families and clinicians at 21 geographically diverse US community/academic pediatric teaching hospitals participated in a prospective cohort dissemination and implementation study. Intervention: We inquired about rounding beliefs/attitudes, practices, and demographics using a 26-question survey coproduced with family/nurse/attending-physician collaborators, informed by prior research and the Consolidated Framework for Implementation Research. Main outcome and measures: Out of 2578 individuals, 1647 (64%) responded to the survey; of these, 1313 respondents participated in FCR and were included in analyses (616 patients/families, 243 nurses, 285 resident physicians, and 169 attending physicians). Beliefs/attitudes regarding the importance of FCR elements varied by role, with resident physicians rating the importance of several FCR elements lower than others. For example, on adjusted multivariable analysis, attending physicians (odds ratio [OR] 3.0, 95% confidence interval [95% CI] 1.2-7.8) and nurses (OR 3.1, 95% CI 1.3-7.4) were much more likely than resident physicians to report family participation on rounds as very/extremely important. Clinician support for key FCR elements was higher than self-reported practice (e.g., 88% believed family participation was important on rounds; 68% reported it often/always occurred). In practice, key elements of FCR were reported to often/always occur only 23%-70% of the time. Result: Support for nurse and family participation in FCR is high among clinicians but varies by role. Physicians, particularly resident physicians, endorse several FCR elements as less important than nurses and patients/families. The gap between attitudes and practice and between clinician types suggests that attitudinal, structural, and cultural barriers impede FCR.
Context: Swimming technique is widely believed to influence performance, but this relationship has rarely been tested objectively using a real-time poolside assessment. Objective: To determine the (1) test-retest reliability, interrater reliability, and criterion validity (live vs video) of real-time poolside assessment of upper limb (UL) errors in front crawl (FC) swimming technique and (2) the relationship between UL errors and FC swimming performance. Design: Cross-sectional reliability, validity, and correlational study. Setting: Swim team practice at a college natatorium. Participants: Thirty-nine Division III college swimmers (21 women and 18 men, age = 19 [1] y, swimming experience = 11 [3] y). Main outcome measures: Seven UL errors in FC swimming technique, many of which involved unnecessary vertical and mediolateral motions, were assessed in real time from outside the pool during swim practice. Test-retest reliability, interrater reliability, and criterion validity were calculated using Cohen kappa (κ) and weighted kappa (κw). Swimming performance was determined by the participants' best FC events relative to the conference records. The correlation between total UL errors and FC swimming performance was assessed with Pearson r. Results: Cohen κ and κw were moderate for the majority of errors, with the following ranges: 0.46 to 0.90 (test-retest), -0.01 to 1.00 (interrater), and 0.36 to 0.66 (criterion validity). There was a significant correlation between total UL errors and FC swimming performance: r(24) = -.59 (P = .001, R2 = .35). Conclusions: Reliability and validity were moderate for the majority of errors. The fewer UL errors swimmers made while practicing FC, the faster their best FC race times tended to be relative to the conference record. UL errors in FC swimming technique explained 35% of the variance in performance.
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8,346 members
Joanne Serembus
  • College of Nursing and Health Professions
J. Richard Weggel
  • Department of Civil, Architectural and Environmental Engineering
Daniel Kleier
  • Department of Chemistry
Mary Osbakken
  • School of Biomedical Engineering, Science and Health Systems
3141 Chestnut Street, 19104, Philadelphia, PA, United States
Head of institution
John Fry