Polymorphic Covalent Organic Frameworks: Molecularly Defined Pore Structures and Iodine Adsorption Property.

Radioactive iodine-capturing materials are urgently needed for the emerging challenges in nuclear waste disposal. The various pore structures of covalent organic frameworks (COFs) render them promising candidates for efficient iodine adsorption. However, the detailed structure-property relationship of COFs in iodine adsorption remains elusive. Herein, two polymorphic COFs with significantly different crystalline structures are obtained based on the same building blocks with varied molecular ratios. The two COFs both have high crystallinity, high specific surface area, and excellent chemical and thermal stability. Compared with the [C4+C4] topology (PyT-2) with an AA stacking form, the [C4+C2] topology (PyT-1) with an AB stacking form has more twisted pore channels and complex ink-bottle pores. At ambient conditions, PyT-1 and PyT-2 both exhibit good adsorption properties for iodine capture either in a gaseous or liquid medium. Remarkably, PyT-1 presents an excellent maximum adsorption capacity (0.635 g g-1), and the adsorption limit of PyT-2 is 0.445 g g-1 in an n-hexane solution with an iodine concentration of 400 mg L-1, which is highly comparable to the state-of-the-art iodine absorption performance. This study provides a guide for the future molecular design strategy toward novel iodine adsorbents.

Recent advances in assembled AIEgens for image-guided anticancer therapy.

Image-guided therapy, with simultaneous imaging and therapy functions, has the potential to greatly enhance the therapeutic efficacy of anticancer therapy, and reduce the incidence of side effects. Fluorescence imaging has the advantages of easy operation, abundant signal, high contrast, and fast response for real-time and non-invasive tracking. Luminogens with aggregation-induced emission characteristics (AIEgens) can emit strong luminescence in an aggregate state, which makes them ideal materials to construct applicative fluorophores for fluorescence imaging. The opportunity for image-guided cancer treatment has inspired researchers to explore the theranostic application of AIEgens combined with other therapy methods. In recent years, many AIEgens with efficient photosensitizing or photothermal abilities have been designed by precise molecular engineering, with superior performance in image-guided anticancer therapy. Owing to the hydrophobic property of most AIEgens, an assembly approach has been wildly utilized to construct biocompatible AIEgen-based nanostructures in aqueous systems, which can be used for image-guided anticancer therapy. In the present review, we summarize the recent advances in the assembled AIEgens for image-guided anticancer therapy. Five types of image-guided anticancer therapy using assembled AIEgens are included: chemotherapy, photodynamic therapy, photothermal therapy, gene therapy, and synergistic therapy. Moreover, a brief conclusion with the discussion of current challenges and future perspectives in this area is further presented.

Organic Single Crystals with High Photoluminescence Quantum Yields Close to 100% and High Mobility for Optoelectronic Devices.

Organic single crystals with excellent optical and electrical properties are critical for the development of organic optoelectronics. Herein, two compounds 9,10-bis([N,N-diphenyl]-4'-phenylethynyl)anthracene (TPA-An) and 9,10-bis([1',3'-diphenyl]-5'-phenylethynyl)anthracene (TBA-An) are synthesized by introducing two different luminescent groups, triphenylamine and 1,3-diphenylbenzene, at the 9,10 positions of anthracene via triple bond connection. Single crystals based on TPA-An and TBA-An with a ribbon morphology obtained through the slow solvent-evaporation method exhibit high photoluminescence quantum yields (PLQYs) of 98% and 99% at room temperature, and remarkable hole mobilities of 0.45 and 0.15 cm2 V-1 s-1 in single-crystal organic field-effect transistors (SC-OFETs). Furthermore, UV phototransistors based on the two single crystals obtain photosensitivities of 1.03 × 103 and 3.45 × 104 , ultrahigh photoresponsivities of 7.19 × 105 and 1.50 × 105 A W-1 , and the detectivities exceeding 1.40 × 1016 and 1.60 × 1017 Jones.

Co-assembly of HPV capsid proteins and aggregation-induced emission fluorogens for improved cell imaging.

In order to improve the cell-imaging ability, and particularly, to extend the bio-application of AIEgen, human papillomavirus (HPV) capsid protein L1 was assembled with the complex of DNA and aggregation-induced emission fluorogen 9,10-distyrylhydrazine (DSAI), where the virus-like particles (VLPs) of HPV encapsulate the complex via electrostatic interaction. The co-assembled nanoparticles, DSAI-DNA@VLPs, showed homogeneous size (∼53 nm), enhanced fluorescence (8 × 2.5-fold), considerable stability (anti-DNase digestion), improved biocompatibility and commendable protection for the DSAI-DNA complex, ensuring virtual brighter imaging in live cells, both for HeLa and normal 293T cell lines.

Label-Free Aptamer-Based Biosensor for Specific Detection of Chloramphenicol Using AIE Probe and Graphene Oxide.

A facile, sensitive, and label-free aptamer-based fluorescent biosensor (aptasensor) for chloramphenicol (CAP) detection was successfully developed based on an aggregation-induced emission (AIE) probe and graphene oxide (GO). In this aptasensor, the specific aptamer of CAP (C-Apt) is used as the recognition part, an AIE molecule, 9,10-distyrylanthracene (DSA) derivative with short alkyl chains (9,10-bis{4-[2-(N,N,N-trimethylammonium)-ethoxy]styrene}anthracene dibromide, DSAC2N), as the fluorescent probe, and GO with a low oxidation degree as the fluorescent quencher. Initially, the AIE probe DSAC2N and C-Apt could be adsorbed on GO through π-stacking interactions, and the fluorescence of DSAC2N could be efficiently quenched due to the energy transfer between DSAC2N and GO. When CAP is added, C-Apt can preferentially bind with CAP and the newly formed complex (C-Apt-CAP) can be released from GO, resulting in the recovery of the fluorescence signal of DSAC2N. Thus, with the aid of GO, turn-on detection of CAP can be readily realized by monitoring the fluorescence signal of DSAC2N from "off" to "on". Under the optimized conditions, the aptasensor exhibits a high sensitivity toward CAP with a limit of detection of 1.26 pg/mL. Besides, we have successfully applied this aptasensor to the detection of CAP in spiked milk.

Green-solvent-processed hybrid solar cells based on donor-acceptor conjugated polyelectrolyte.

In this work, a quaternary ammonium side chain modified conjugated polyelectrolyte PFBTBr, with excellent solubility in nonaromatic and nonhalogenated solvents, was designed and synthesized as the donor material for the green-solvent-processed hybrid solar cells (HSCs). By introducing the donor-acceptor structure, PFBTBr shows a lower lying highest occupied molecular orbital (HOMO) level and a broad absorption from 300 to 700 nm. Incorporating the water soluble CdTe nanocrystals (NCs) as acceptor, the green-solvent-processed HSCs based on conjugated polyelectrolyte and inorganic NCs were fabricated. Through the active layer optimization, a well blended donor/acceptor active layer with continuous electron/hole transport pathway and smoother surface was achieved. As a result, a photovoltaic efficiency of 3.67% was realized. After the further interfacial modification and chloride treatment, the power conversion efficiency of the green-solvent-processed HSCs was improved to 5.03% with the maximum external quantum efficiency value of 87.01% at 400 nm under the AM 1.5 G 100 mW cm-2 illumination.

Comparative effects of low-dose versus standard-dose alteplase in ischemic patients with prior stroke and/or diabetes mellitus: The ENCHANTED trial.

BACKGROUND AND PURPOSE: History of prior stroke (PS) and diabetes mellitus (DM) are considered relative contraindications to the use of intravenous alteplase in patients with acute ischemic stroke (AIS). We aimed to assess whether a history of PS and DM modified the comparative effects of low- versus standard-dose alteplase in patients who participated in the alteplase-dose arm of the Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED). METHODS: Data from an international, multi-center, prospective, randomized, open-label, blinded-endpoint trial were used to assess the benefits and risks of low (0.6mg/kg) versus standard-dose (0.9mg/kg) intravenous alteplase in thrombolysis-eligible AIS patients. Logistic regression was used for analysis of patient subgroups defined by history of PS and DM on efficacy and safety outcomes, adjusted for confounding variables. RESULTS: After adjusting for baseline characteristics and management variables over the first seven days in 3288 AIS patients (431 PS, 489 DM, and 157 with both), history of PS and DM were not associated with poor outcome at 90-days: whether defined by modified Rankin scale (mRS) scores 2-6 (odds ratio [OR] 0.85, 95% confidence interval [CI] 0.55-1.32; P=0.476) or mortality (OR 1.25, 95%CI 0.62-2.52; P=0.533). There was no differential effect of low-versus standard-dose alteplase on dichotomized mRS (0-1 vs. 2-6), ordinal shift in mRS scores, mortality, or symptomatic intracerebral hemorrhage, by a history of PS and DM. CONCLUSIONS: A history of PS and DM was not an independent predictor of poor outcome in thrombolysis-treated AIS patients. We were not able to demonstrate any effect of these variables in modifying the differences in effects of low- versus standard-dose alteplase. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01422616.

Silica nanoparticles based on an AIE-active molecule for ratiometric detection of RNS in vitro.

Nitric oxide (NO), known as a reactive nitrogen species (RNS), has been considered to be a significant factor in many cell-related biological processes. There is a great desire to develop fluorescent probes that can highly sensitively and selectively detect NO in living cells. Herein, a fluorescent probe, a tetraphenylethene (TPE) derivative TPE-2NH2, with aggregation induced emission (AIE) properties was designed and synthesized. Then silica nanoparticles based on TPE-2NH2 were fabricated for ratiometric detection of NO in vitro with high sensitivity and selectivity. In the presence of NO, the fluorescence of the silica nanoparticles changes from 519 nm (green) to 655 nm (red) because of the chemical reaction between NO and o-phenylenediamine in TPE-2NH2. The silica nanoparticles exhibited very high sensitivity and selectivity towards NO in aqueous buffer, and the response time was as short as 5 minutes. Moreover, the silica nanoparticles can also highly sensitively and selectively respond to NO produced in living cells. When MCF-7 cancer cells were activated by lipopolysaccharides (LPS), which can effectively induce the production of NO, the red emission signal of the silica nanoparticles obviously increased. This demonstrated that the silica nanoparticles showed fine imaging contrast towards NO in MCF-7 cancer cells, which provides a facile tool to detect intracellular NO.

Magnesium-doped Zinc Oxide as Electron Selective Contact Layers for Efficient Perovskite Solar Cells.

The electron-selective contact layer (ESL) in organometal halide-based perovskite solar cells (PSCs) determines not only the power conversion efficiency (PCE) but also the thermostability of PSCs. To improve the thermostability of ZnO-based PSCs, we developed Mg-doped ZnO [Zn1-x Mgx O (ZMO)] as a high optical transmittance ESL for the methylammonium lead trihalide perovskite absorber [CH3 NH3 PbI3 ]. We further investigated the optical and electrical properties of the ESL films with Mg contents of 0-30 mol % and the corresponding devices. We achieved a maximum PCE of 16.5 % with improved thermal stability of CH3 NH3 PbI3 on ESL with the optimal ZMO (0.4 m) containing 10 mol % Mg. Moreover, this optimized ZMO PSC exhibited significantly improved durability and photostability owing to the improved chemical/photochemical stability of the wider optical bandgap ZMO.

Early prediction of death in acute hypertensive intracerebral hemorrhage.

Hypertensive intracerebral hemorrhage (HICH) has been on the decline. However, mortality at long-term follow up is on the increase. The aim of the present study was to investigate early warning signals of death in patients with acute HICH. The medical records of 128 patients with acute HICH within 6 h of onset were retrospectively analyzed. For these patients, systolic blood pressure (BP) was recorded at different time points (emergency, admission, every 6 h within 24 h and twice daily after 24 h) within 1 week. Computed tomography scanning was performed at emergency and the following 24±3 h to assess the hematoma volume. Neurological impairment was evaluated using the Glasgow Coma Scale and National Institutes of Health Stroke Scale. Outcomes were death, defined as a modified Rankin scale score 6, at 90 days. The results showed that at 90 days, 15 HICH patients succumbed (mortality of 11.7%). Of the 15 patients, 1 patient (6.7%) sucumbed within 24 h and 6 patients (40%) within 1 week. HICH mortality was closely associated with age (P<0.001) but not with gender. A significant association was detected between mortality and high BP taken at 30 min, 45 min and 6 h after admission (P=0.003), albeit not at emergency and admission (P>0.05). Death was also correlated with hematoma volume at 24 h but not with the site. Results from the multivariate binary logistic regression analysis showed that age and hematoma volume were independent risk factors of death of HICH. In conclusion, age and hematoma volume may be important early predictors of death in HICH. Proactive control and management of hematoma may reduce the mortality of HICH.