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Small-molecule thermally activated delayed fluorescence (TADF) materials have been extensively developed to actualize efficient organic LEDs (OLEDs). However, organic small molecules generally compromise thin film quality and stability due to the tendency of crystallization, aggregation, and phase separation, which hence degrade the efficiency and long-term stability of the OLEDs. Here, for the first time, we exploit the unique molecular configuration of the bimesitylene scaffold to design two highly efficient TADF amorphous molecular materials with excellent thermal and morphological stabilities. The twisted and rigid bimesitylene scaffold thwarts regular molecular packing and crystallization, thereby guaranteeing homogeneous and stable amorphous thin films. Meanwhile, the highly twisted geometry of the bimesitylene scaffold efficiently breaks the molecular conjugation and thus conserves the high energies of the lowest locally excited triplet states (3LE) above the lowest charge transfer states (1CT and 3CT), leading to small singlet-triplet energy splitting and fast reverse intersystem crossing. These TADF emitters exhibit high photoluminescence quantum yields of 0.90 and 0.69 and short TADF lifetimes of 4.94 and 1.44 μs in doped films, based on which the greenish-blue and greenish-yellow OLEDs achieve external quantum efficiencies of 23.2 and 16.2%, respectively, with small efficiency roll-off rates and perfect color stability.

Solvothermal reaction of tBuC≡CAg, AgBF4 and nicotinic/isonicotinic acid in acetonitrile afforded two new silver(I) tert-butylethynide double salts, namely [(tBuC≡CAg)(AgL1)3] (HL1 = nicotinic acid) (1) and [(tBuC≡CAg)(AgL1)2] (HL2 = isonicotinic acid) (2). These compounds have been characterized by elemental analysis, infrared spectra, single-crystal X-ray analysis, X-ray powder diffraction, thermogravimetric analysis, UV–visible absorption spectra, and luminescent measurement. 1 exhibits a two-dimensional coordination network, and 2 features a three-dimensional coordination architecture. Luminescence measurements indicate that 1 shows a fluorescent emission band centered at 568 nm, and 2 exhibits an intense emission maximum at 550 nm and a shoulder peak at 436 nm.

BACKGROUND Comprehensive analyses are lacking to identify predictors of postoperative complications in patients who undergo a Hartmann reversal. OBJECTIVE The aim of this study is to identify predictive factors for morbidity after reversal. DESIGN This study is a retrospective review of prospectively collected data. SETTINGS The study was conducted at Cleveland Clinic Florida. PATIENTS Consecutive patients from January 2004 to July 2011 who underwent reversal were included. MAIN OUTCOME MEASURES Variables pertaining to Hartmann procedure and reversal were obtained for analyses in patients with and without postoperative complications. Univariate and multivariate analyses were performed. RESULTS A total of 95 patients (mean age 61 years, 56% male) underwent reversal, with an overall morbidity of 46%. Patients with and without complications had similar demographics, comorbidities, diagnoses, and Hartmann procedure intraoperative findings. Patients with complications after reversal were more likely to have prophylactic ureteral stents (61% vs 41%, p < 0.05) and an open approach (91% vs 75%, p < 0.04). Complications were associated with longer hospital stay (8.8 vs 6.9 days,p < 0.006) and higher rates of reintervention (9% vs 0%, p < 0.03) and readmission (16% vs 2%, p < 0.02). Predictors of morbidity after reversal included BMI (29 vs 26 kg/m, p < 0.04), hospital stay for Hartmann procedure (15 vs 10 days, p < 0.03), and short distal stump (50% vs 31%, p < 0.05). BMI was the only independent predictor of morbidity (p < 0.04). Obesity was associated with significantly greater overall morbidity (64% vs 40%, p < 0.04), wound infections (56% vs 31%, p < 0.04), diverting ileostomy at reversal (24% vs 13%, p < 0.05), and time between procedures (399 vs 269 days, p < 0.02). LIMITATIONS This study was limited by its retrospective design. CONCLUSIONS Hartmann reversal is associated with significant morbidity; BMI independently predicts complications. Therefore, patients who are obese should be encouraged or even potentially required to lose weight before reversal.

This paper presents a detailed analysis of RF system parameters, including phase noise, noise figure, the in-band third-order intercept point (IIP3), the in-band second-order intercept point (IIP2), and the in-phase/quadrature (I/Q) imbalance, of the direct conversion receiver (DCR) for an 802.11a wireless local-area-network (WLAN) orthogonal frequency-division-multiplexing system. A design example of DCR RF parameters planning for a 5-GHz 802.11a WLAN is presented and discussed. It is found that the critical specifications to realize a 5-GHz 802.11a WLAN DCR are the local-oscillator phase noise and I/Q imbalance. However, since there is a 312.5-kHz empty region around zero frequency for the 802.11a standard, dc offset and flicker noise are less sensitive. Hence, the DCR architecture is still an attractive choice for the 802.11a WLAN system. The study can be very useful for RF circuit design in wireless-communication systems.

No prediction rule is currently available for advanced colorectal neoplasms, defined as invasive cancer, an adenoma of 10 mm or more, a villous adenoma, or an adenoma with high-grade dysplasia, in average-risk Chinese. In this study between 2006 and 2008, a total of 7,541 average-risk Chinese persons aged 40 years or older who had complete colonoscopy were included. The derivation and validation cohorts consisted of 5,229 and 2,312 persons, respectively. A prediction rule was developed from a logistic regression model and then internally and externally validated. The prediction rule comprised 8 variables (age, sex, smoking, diabetes mellitus, green vegetables, pickled food, fried food, and white meat), with scores ranging from 0 to 14. Among the participants with low-risk (≤3) or high-risk (>3) scores in the validation cohort, the risks of advanced neoplasms were 2.6% and 10.0% (P < 0.001), respectively. If colonoscopy was used only for persons with high risk, 80.3% of persons with advanced neoplasms would be detected while the number of colonoscopies would be reduced by 49.2%. The prediction rule had good discrimination (area under the receiver operating characteristic curve = 0.74, 95% confidence interval: 0.70, 0.78) and calibration (P = 0.77) and, thus, provides accurate risk stratification for advanced neoplasms in average-risk Chinese.