17 research outputs found

    The Role of Shift Vector in High-Harmonic Generation from Non-Centrosymmetric Topological Insulators under Strong Laser Fields

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    As a promising avenue to obtain new extreme ultraviolet light source and detect electronic properties, high-harmonic generation (HHG) has been actively developed in both theory and experiment. In solids lacking inversion symmetry, when electrons undergo a nonadiabatic transition, a directional charge shift occurs and is characterized by shift vector, which measures the real-space shift of the photoexcited electron and hole. For the first time, we have revealed that shift vector plays prominent roles in the real-space tunneling mechanism of three-step model for electrons under strong laser fields. Since shift vector is determined by the topological properties of related wave functions, we expect HHG with its contribution can provide direct knowledge on the band topology in noncentrosymmetric topological insulators (TIs). In both Kane-Mele model and realistic material BiTeI, we have found that the shift vector reverses when band inversion happens during the topological phase transition between normal and topological insulators. Under oscillating strong laser fields, the reversal of shift vector leads to completely opposite radiation time of high-order harmonics. This makes HHG a feasible all-optical strong-field method to directly identify the band inversion in non-centrosymmetric TIs.Comment: 25 pages, 12 figure

    iMStrong: Deployment of a Biosensor System to Detect Cocaine Use

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    Biosensor systems are increasingly promoted for use in behavioral interventions. Portable biosensors might offer advancement over self-report use and can provide improved opportunity for detection and intervention in patients undergoing drug treatment programs. Fifteen participants wore a biosensor wristband capable of detecting multiple physiologic markers of sympathetic nervous system (SNS) arousal for 30 days. Urine drug screening and drug use self-report were obtained twice per week. A parameter trajectory description method was applied to capture abrupt changes in magnitude of three measures of SNS activity: Electrodermal activity (EDA), skin temperature and motion. Drug use events detected by the biosensor were verified using a triad of parameters: the biosensor data, urine drug screens, and patient self-report of substance use. Twelve positive cocaine urine screens were identified. Thirteen self-reported episodes of cocaine use were recorded. Distinct episodes with biometric parameters consistent with cocaine use were identified on biosensor data. Eleven potential cocaine use episodes were identified by biosensors that were missed by both self-report and drug screening. Study participants found mobile biosensors to be acceptable, and compliance with the protocol was high. Episodes of cocaine use, as measured by supraphysiologic changes in biophysiometric parameters, were detected by analysis of biosensor data in instances when self-report or drug screening or both failed. Biosensors have substantial potential in detecting substance abuse, in understanding the context of use in real time, and in evaluating the efficacy of behavioral interventions for drug abuse

    Patterns and predictors of cancer-related fatigue in ovarian and endometrial cancers: 1-year longitudinal study

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    Background:  Fatigue is a common and distressing symptom for patients with gynecologic cancers. Few studies have empirically examined whether it spontaneously resolves. This study was aimed at identifying longitudinal patterns of fatigue and predictors of clinically significant fatigue 1 year after treatment completion. Methods:  This was a prospective cohort study of women with newly diagnosed ovarian (n = 81) or endometrial cancer (n = 181) that did not progress or recur within 1 year of treatment completion. Symptoms of fatigue, depression, and anxiety were assessed after surgery and 6 and 12 months after treatment completion with the Fatigue Assessment Scale and the Hospital Anxiety and Depression Scale. Patients' fatigue scores over time were classified (scores of 22-50, clinically significant; scores of 10-21, not clinically significant). Logistic regression models were fit to examine associations between fatigue and patient characteristics. Results:  Among 262 participants, 48% reported clinically significant fatigue after surgery. One year later, 39% reported fatigue. There were 6 patterns over time: always low (37%), always high (25%), high then resolves (18%), new onset (10%), fluctuating (6%), and incidental (5%). Patients with fatigue after surgery were more likely to report fatigue at 12 months in comparison with others (odds ratio [OR], 6.08; 95% confidence interval [CI], 2.82-13.11; P < .001). Patients with depressive symptoms also had higher odds of fatigue (OR, 3.36; 95% CI, 1.08-10.65; P = .039), although only one-third of fatigued patients reported depressive symptoms. Conclusion:  Nearly half of women with gynecologic cancers had clinically significant fatigue after surgery, whereas 44% and 39% had fatigue 6 months and 1 year later; this suggests that spontaneous regression of symptoms is relatively rare. Women who reported fatigue, depressive symptoms, or 2 or more medical comorbidities had higher odds of reporting fatigue 1 year later. Future studies should test scalable interventions to improve fatigue in women with gynecologic cancers

    Patterns and predictors of cancer‐related fatigue in ovarian and endometrial cancers: 1‐year longitudinal study

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    Background:  Fatigue is a common and distressing symptom for patients with gynecologic cancers. Few studies have empirically examined whether it spontaneously resolves. This study was aimed at identifying longitudinal patterns of fatigue and predictors of clinically significant fatigue 1 year after treatment completion. Methods:  This was a prospective cohort study of women with newly diagnosed ovarian (n = 81) or endometrial cancer (n = 181) that did not progress or recur within 1 year of treatment completion. Symptoms of fatigue, depression, and anxiety were assessed after surgery and 6 and 12 months after treatment completion with the Fatigue Assessment Scale and the Hospital Anxiety and Depression Scale. Patients' fatigue scores over time were classified (scores of 22-50, clinically significant; scores of 10-21, not clinically significant). Logistic regression models were fit to examine associations between fatigue and patient characteristics. Results:  Among 262 participants, 48% reported clinically significant fatigue after surgery. One year later, 39% reported fatigue. There were 6 patterns over time: always low (37%), always high (25%), high then resolves (18%), new onset (10%), fluctuating (6%), and incidental (5%). Patients with fatigue after surgery were more likely to report fatigue at 12 months in comparison with others (odds ratio [OR], 6.08; 95% confidence interval [CI], 2.82-13.11; P < .001). Patients with depressive symptoms also had higher odds of fatigue (OR, 3.36; 95% CI, 1.08-10.65; P = .039), although only one-third of fatigued patients reported depressive symptoms. Conclusion:  Nearly half of women with gynecologic cancers had clinically significant fatigue after surgery, whereas 44% and 39% had fatigue 6 months and 1 year later; this suggests that spontaneous regression of symptoms is relatively rare. Women who reported fatigue, depressive symptoms, or 2 or more medical comorbidities had higher odds of reporting fatigue 1 year later. Future studies should test scalable interventions to improve fatigue in women with gynecologic cancers
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