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Background: Stroke is a severe neurologic complication of dengue fever, described in only a few case reports. The incidence and risk factors for stroke in patients with dengue remain unclear. We conducted a population-based retrospective cohort study to investigate the risk of stroke in patients with dengue.Methods: Using data from the Taiwan National Health Insurance Research Database, we included a total of 13 787 patients with dengue newly diagnosed between 2000 and 2012. The control cohort consisted of patients who did not have dengue, matched 1:1 by demographic characteristics and stroke-related comorbidities. We calculated the cumulative incidences and hazard ratios (HRs) of stroke in both cohorts using Kaplan-Meier curves and Cox proportional hazards regression.Results: The overall incidence rate of stroke was 5.33 per 1000 person-years in the dengue cohort and 3.72 per 1000 person-years in the control cohort, with an adjusted HR of 1.16 (95% confidence interval [CI] 1.01-1.32). The risk of stroke among patients with dengue was highest in the first 2 months after diagnosis (25.53 per 1000 person-years, adjusted HR 2.49, 95% CI 1.48-4.18).Interpretation: Dengue fever was associated with an increased risk of stroke in the first few months after diagnosis. The effect of dengue on stroke may be acute rather than chronic. [ABSTRACT FROM AUTHOR]

Organic small molecular materials with coplanar π-conjugated system as HTMs in perovskite solar cells (PSCs) have attracted considerable attention due to their high charge transport capability and thermal stability. Herein, three novel pentafulvalene-fused derivatives with or without fluorine atoms incorporated (YSH-oF and YSH-mF and YSH-H, respectively) are designed, synthesized, and applied as hole-transporting materials (HTMs) in PSCs fabrication. The fluorinated HTMs, YSH-oF and YSH-mF, exhibited higher hole mobility and better charge extraction at the perovskite/HTM interface than non-fluorinated one do, presumably due to the closer intermolecular π-π packing interactions. As a result, small-area (0.09 cm2) PSCs made with YSH-oF and YSH-mF achieved an impressive power conversion efficiency (PCE) of 23.59% and 22.76% respectively, with negligible hysteresis, in contrast with the 20.57% for the YSH-H-based devices. Furthermore, for large-area (1.00 cm2) devices, the PSCs employing YSH-oF exhibited a PCE of 21.92%. Moreover, excellent long-term device stability is demonstrated for PSCs with F-substituted HTMs (YSH-oF and YSH-mF), presumably due to the higher hydrophobicity. This study shows the great potential of fluorinated pentafulvalene-fused materials as low-cost HTM for efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Abstract Nanocrystalline NbB 2 powder has been synthesized via a single step solid-state reaction of precursor materials Nb 2 O 5 and NaBH 4. Phase composition, grain morphology, microstructure, phonon vibrations and superconducting properties were investigated by XRD, FESEM, HRTEM, Raman spectroscopy and PPMS. The results show that the grain size of nanocrystalline NbB 2 is very sensitive to the reaction temperature and easy to aggregate to form micron scale of non-morphology powders. A systematic increase of the electron-phonon coupling constant with the nanoscaling grain size is observed, which we explain in terms of crystal defects and phonon vibrations. The zero-temperature critical fields, H c 1 (0) and H c 2 (0), have been estimated at 85 Oe and 7200 Oe, respectively, and the Ginzburg–Landau parameter κ is 5.1, confirming that NbB 2 is a type-II superconductor. Highlights • Single-phased NbB 2 nanocrystalline has been synthesized by a solid-state reaction in a continuous evacuating process. • The reaction temperature has an important effect on the grain size. • A systematic increase of the electron-phonon coupling constant with the nanoscaling grain size is observed. [ABSTRACT FROM AUTHOR]

Aims: Concerns about acute pelvic inflammatory disease (PID) after hysterosalpingography (HSG) have been raised since 1980. However, the effectiveness of prophylactic antibiotics remains unclear. This study investigated the effect of antibiotic prophylaxis in women undergoing HSG.Methods: Women undergoing HSG between 2000 and 2012 were screened from the Taiwan National Health Insurance Research Database for eligibility. The prophylactic cohort included patients using any antibiotics of 1st-generation cephalosporins, doxycycline, clindamycin, and metronidazole, within 7 days before HSG (n = 3257). Patients not using any antibiotics were registered as the non-prophylactic cohort (n = 4662). An unconditional logistic regression model was applied to calculate the odds ratio (OR) and 95% confidence interval (CI) of acute PID after HSG associated with prophylactic antibiotics.Results: The cumulative incidences of acute PID after HSG were 0.46% and 1.42% in the prophylactic and non-prophylactic cohorts, respectively. Prophylactic patients had a significantly reduced estimated relative risk of acute PID compared with non-prophylactic patients (adjusted OR = 0.33, 95% CI = 0.19-0.58; p = .001). Doxycycline users had the lowest adjusted OR of 0.20 (95% CI = 0.04-0.81; p = .02), followed by users of 1st-generation cephalosporins (adjusted OR = 0.35, 95% CI = 0.18-0.68; p = .002). Multivariate sub-group analysis verified this protective effect for almost all sub-groups of prophylactic patients.Conclusions: Antibiotic prophylaxis is associated with a decreased estimated relative risk of acute PID in HSG patients. Doxycycline and 1st-generation cephalosporins may be effective prophylactic regimens for HSG. [ABSTRACT FROM AUTHOR]

Objective: The incidence and association between appendicitis and barium examination (BE) remain unclear. Such potential risk may be omitted. We conducted a longitudinal, nationwide, population-based cohort study to investigate the association between BE and appendicitis risk.Methods: From the Taiwan National Health Insurance Research Database, a total of 24,885 patients who underwent BE between January 1, 2000 and December 31, 2010 were enrolled in a BE cohort; an additional 98,384 subjects without BE exposure were selected as a non-BE cohort, matched by age, sex, and index date. The cumulative incidences of subsequent appendicitis in the BE and non-BE cohorts were assessed using the Kaplan-Meier curves and log-rank test. Cox proportional hazards regression analyses were employed to calculate the appendicitis risk between the groups.Results: The cumulative incidence of appendicitis was higher in the BE cohort than in the non-BE cohort (P = .001). The overall incidence rates of appendicitis for the BE and non-BE cohorts were 1.19 and 0.80 per 1000 person-years, respectively. After adjustment for sex, age, and comorbidities, the risk of appendicitis was higher in the BE cohort (adjusted hazard ratio = 1.46, 95% confidence interval = 1.23-1.73) compared with the non-BE cohort, especially in the first 2 months (adjusted hazard ratio = 9.72, 95% confidence interval = 4.65-20.3).Conclusions: BE was associated with an increased, time-dependent appendicitis risk. Clinicians should be aware of this potential risk to avoid delayed diagnoses. [ABSTRACT FROM AUTHOR]

Abstract: The high quality La x Ce1− x B6 (x =0, 0.2, 0.4, 0.6, 1) single crystals with large emission current density have been successfully grown by floating zone method. The crystal structure, crystal quality and emission properties of La x Ce1−xB6 single crystals were characterized by 360° Phi scanning single crystal diffractometer, X-ray Laue diffraction and the thermal electron emission measurements. It is found that the as-grown crystals have a good crystal quality without subgrains and twin crystal phenomenon. The thermionic emission measurement results show that the maximum emission current density on (100) surface of La0.2Ce0.8B6 single crystal is 71.2A/cm2 at 1873K under an applied voltage of 800V, which is larger than the reported values in the literatures up to now. Furthermore, the crystals with different components also show a higher emission current density such as 53.8A/cm2 for La0.4Ce0.6B6 and 53.3A/cm2 for CeB6 single crystals. The field emission single tip made by LaB6 single crystal shows a superior performance than the polycrystalline LaB6 field emission tip and its field enhancement factor (β) is 36,231cm−1. Thus, the La x Ce1− x B6 single crystals will have promising application prospects as a hot or cold cathode. [Copyright &y& Elsevier]