Strongly emitting, centrosymmetric, ladder-type bis-coumarins with crankshaft architecture.

Quadrupolar bis-coumarins bearing dialkylamino groups, prepared by a double Pechmann reaction and subsequent oxidation, strongly emit yellow-orange light. Comparison with non-substituted analogs reveals that, the photophysical properties of the conjugated bis-coumarins are controlled both by the dialkylamino substituents and by the π-system. Analogous but non-conjugated bis-coumarins emit blue light both in solution and in crystalline state. Unusually fast oxidation process in the crystalline state is responsible for the presence of two bands in their solid-state emission. Two-center, charge-transfer transition from an orbital delocalized on the entire molecule to the central benzene ring is responsible for photophysical properties.

Amphiphilic Diblock Copolymers Bearing Poly(Ethylene Glycol) Block: Hydrodynamic Properties in Organic Solvents and Water Micellar Dispersions, Effect of Hydrophobic Block Chemistry on Dispersion Stability and Cytotoxicity.

Despite the fact that amphiphilic block copolymers have been studied in detail by various methods both in common solvents and aqueous dispersions, their hydrodynamic description is still incomplete. In this paper, we present a detailed hydrodynamic study of six commercial diblock copolymers featuring the same hydrophilic block (poly(ethylene glycol), PEG; degree of polymerization is ca. 110 ± 25) and the following hydrophobic blocks: polystyrene, PS35-b-PEG115; poly(methyl methacrylate), PMMA55-b-PEG95; poly(1,4-butadyene), PBd90-b-PEG130; polyethylene PE40-b-PEG85; poly(dimethylsiloxane), PDMS15-b-PEG115; and poly(ɛ-caprolactone), PCL45-b-PEG115. The hydrodynamic properties of block copolymers are investigated in both an organic solvent (tetrahydrofuran) and in water micellar dispersions by the combination of static/dynamic light scattering, viscometry, and analytical ultracentrifugation. All the micellar dispersions demonstrate bimodal particle distributions: small compact (hydrodynamic redii, Rh ≤ 17 nm) spherical particles ascribed to "conventional" core-shell polymer micelles and larger particles ascribed to micellar clusters. Hydrodynamic invariants are (2.4 ± 0.4) × 10-10 g cm2 s-2 K-1 mol-1/3 for all types of micelles used in the study. For aqueous micellar dispersions, in view of their potential biomedical applications, their critical micelle concentration values and cytotoxicities are also reported. The investigated micelles are stable towards precipitation, possess low critical micelle concentration values (with the exception of PDMS15-b-PEG115), and demonstrate low toxicity towards Chinese Hamster Ovarian (CHO-K1) cells.

Aggregation-Induced Ignition of Near-Infrared Phosphorescence of Non-Symmetric [Pt(C

In the present work, we described the preparation and characterization of the micelles based on amphiphilic poly(ε-caprolactone-block-ethylene glycol) block copolymer (PCL-b-PEG) loaded with non-symmetric [Pt(C^N*N'^C')] complex (Pt1) (where C^N*N'^C': 6-(phenyl(6-(thiophene-2-yl)pyridin-2-yl)amino)-2-(tyophene-2-yl)nicotinate). The obtained nanospecies displayed the ignition of near-infrared (NIR) phosphorescence upon an increase in the content of the platinum complexes in the micelles, which acted as the major emission component at 12 wt.% of Pt1. Emergence of the NIR band at 780 nm was also accompanied by a 3-fold growth of the quantum yield and an increase in the two-photon absorption cross-section that reached the value of 450 GM. Both effects are believed to be the result of progressive platinum complex aggregation inside hydrophobic poly(caprolactone) cores of block copolymer micelles, which has been ascribed to aggregation induced emission (AIE). The resulting phosphorescent (Pt1@PCL-b-PEG) micelles demonstrated pronounced sensitivity towards molecular oxygen, the key intracellular bioanalyte. The detailed photophysical analysis of the AIE phenomena revealed that the NIR emission most probably occurred due to the excimeric excited state of the 3MMLCT character. Evaluation of the Pt1@PCL-b-PEG efficacy as a lifetime intracellular oxygen biosensor carried out in CHO-K1 live cells demonstrated the linear response of the probe emission lifetime towards this analyte accompanied by a pronounced influence of serum albumin on the lifetime response. Nevertheless, Pt1@PCL-b-PEG can serve as a semi-quantitative lifetime oxygen nanosensor. The key result of this study consists of the demonstration of an alternative approach for the preparation of NIR biosensors by taking advantage of in situ generation of NIR emission due to the nanoconfined aggregation of Pt (II) complexes inside the micellar nanocarriers.

Association of Permanent Vascular Access Dysfunction with Subsequent Risk of Cardiovascular Disease: A Population-Based Cohort Study.

A functional permanent vascular access (VA) is required to perform a successful hemodialysis procedure. Hemodialysis VA dysfunction is a major cause of morbidity and hospitalization in the hemodialysis population. Cardiovascular disease (CVD) is the leading cause of death in patients receiving chronic hemodialysis. Information about CVD associated with hemodialysis VA dysfunction is unclear. We analyzed the association between dialysis VA dysfunction and the risk of developing CVD in hemodialysis patients. This nationwide population-based cohort study was conducted using data from the National Health Insurance Research Database in Taiwan. One million subjects were sampled from 23 million beneficiaries and data was collected from 2000 to 2013. Patients with end-stage renal disease who had received permanent VA construction and hemodialysis and were aged at least 20 years old from 2000 to 2007 were included in the study population. The primary outcome was CVD, as defined by ICD-9-CM codes 410-414 and 430-437. A total of 197 individuals with permanent VA dysfunction were selected as the test group, and 100 individuals with non-permanent VA dysfunction were selected as the control group. Compared with the control group, the adjusted hazard ratio of CVD for the VA dysfunction group was 3.05 (95% CI: 1.14-8.20). A Kaplan-Meier analysis revealed that the cumulative incidence of CVD was higher in the permanent VA dysfunction group than in the comparison group. Permanent VA dysfunction is significantly associated with an increased risk of subsequent CVD.

Homoleptic Ir(III) Phosphors with 2-Phenyl-1,2,4-triazol-3-ylidene Chelates for Efficient Blue Organic Light-Emitting Diodes.

In this report, we synthesized two series of deep-blue-emitting homoleptic iridium(III) phosphors bearing 1,2,4-triazol-3-ylidene and 5-(trifluoromethyl)-1,2,4-triazol-3-ylidene cyclometalate. Compared with reported synthetic routes using Ag2O as the promoter, herein, we adopted a different strategy to furnish these complexes in high yields. Also, the meridional to facial isomerization was executed in the presence of trifluoroacetic acid. These phosphors were examined using NMR spectroscopies, single-crystal X-ray diffraction studies, and photophysical methods. The results revealed that electron-withdrawing trifluoromethyl substitution on the N-heterocyclic carbene fragment only gave a minor variation of photoluminescence peak wavelengths and a decrease in radiative lifetime but notable reduction in thermal stabilities. The parent 1,2,4-triazol-3-ylidene complexes have been demonstrated to be suitable for use as deep-blue phosphors, with structured emission with the peak max. located at ∼420 nm and with photoluminescence quantum yields in a range of 34.8-42.5% in degassed THF solution at RT. Fabrication of both the phosphorescent organic light-emitting diodes (OLEDs) and phosphor-sensitized OLEDs (or hyperphosphorescence) was successfully conducted, from which the OLED device based on m-tz1 showed a max. external quantum efficiency (EQE) of 10% with CIEx,y coordinates of 0.15, 0.06, while the corresponding hyperphosphorescent OLED using m-tz2 as a sensitizer and t-DABNA as a terminal emitter afforded a significantly improved max. EQE of 19.7%, EL λmax of 468 nm, and FWHM of 31 nm with CIEx,y coordinates of 0.12, 0.13.

Chapter Open for the Excited-State Intramolecular Thiol Proton Transfer in the Room-Temperature Solution.

We report here, for the first time, the experimental observation on the excited-state intramolecular proton transfer (ESIPT) reaction of the thiol proton in room-temperature solution. This phenomenon is demonstrated by a derivative of 3-thiolflavone (3TF), namely, 2-(4-(diethylamino)phenyl)-3-mercapto-4H-chromen-4-one (3NTF), which possesses an -S-H···O═ intramolecular H-bond (denoted by the dashed line) and has an S1 absorption at 383 nm. Upon photoexcitation, 3NTF exhibits a distinctly red emission maximized at 710 nm in cyclohexane with an anomalously large Stokes shift of 12 230 cm-1. Upon methylation on the thiol group, 3MeNTF, lacking the thiol proton, exhibits a normal Stokes-shifted emission at 472 nm. These, in combination with the computational approaches, lead to the conclusion of thiol-type ESIPT unambiguously. Further time-resolved study renders an unresolvable (<180 fs) ESIPT rate for 3NTF, followed by a tautomer emission lifetime of 120 ps. In sharp contrast to 3NTF, both 3TF and 3-mercapto-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one (3FTF) are non-emissive. Detailed computational approaches indicate that all studied thiols undergo thermally favorable ESIPT. However, once forming the proton-transferred tautomer, the lone-pair electrons on the sulfur atom brings non-negligible nπ* contribution to the S1' state (prime indicates the proton-transferred tautomer), for which the relaxation is dominated by the non-radiative deactivation. For 3NTF, the extension of π-electron delocalization by the diethylamino electron-donating group endows the S1' state primarily in the ππ* configuration, exhibiting the prominent tautomer emission. The results open a new chapter in the field of ESIPT, covering the non-canonical sulfur intramolecular H-bond and its associated ESIPT at ambient temperature.

Cyano Derivatives of 7-Aminoquinoline That Are Highly Emissive in Water: Potential for Sensing Applications.

6-Cyano-7-aminoquinoline (6CN-7AQ) and 3-cyano-7-aminoquinoline (3CN-7AQ) were synthesized and found to exhibit intense emission with quantum yield as high as 63 % and 85 %, respectively, in water. Conversely, their derivatives 6-cyano-7-azidoquinoline (6CN-7N3 Q) and 3-cyano-7-azidoquinoline (3CN-7N3 Q) show virtually no emission, which makes them suitable to be used as recognition agents in azide reactions based on fluorescence recovery. Moreover, conjugation of 6CN-7AQ with a hydrophobic biomembrane-penetration peptide PFVYLI renders a nearly non-emissive 6CN-7AQ-PFVYLI composite, which can be digested by proteinase K, recovering the highly emissive 6CN-7AQ with ∼200-fold enhancement. The result provides an effective early confirmation for RT-qPCR in viral detection.

Serum Uric Acid Level as a Harbinger of Type 2 Diabetes: A Prospective Observation in Taiwan.

BACKGROUND: Current evidence suggests an association of uric acid with diabetes risk, but it is still unclear whether uric acid is merely a risk marker or an independent risk factor. We evaluate the impact of serum uric acid (SUA) levels on the future risk of developing type 2 diabetes, independent of other factors. METHODS: A population-based cohort study was conducted among 4130 participants who were found to be free of type 2 diabetes at baseline recruitment in 2002. Baseline SUA measured in 2002 was longitudinally related to the incident type 2 diabetes that occurred during the follow-up period between 2002 and 2007. Hazard ratios (HRs) and 95% confidence intervals (CIs) derived from Cox proportional hazards models were used to quantify the association. RESULTS: There was a graded increase in the incidence of type 2 diabetes among individuals with increasing levels of SUA. In the whole study cohort, compared to quartile 1, the multivariable-adjusted HRs (95% CIs) of type 2 diabetes in quartile 2, quartile 3, and quartile 4 were 1.69 (0.76-3.76), 1.86 (0.88-4.26), and 1.94 (1.05-4.05), respectively (P for trend = 0.004). This positive gradient for the risk of type 2 diabetes across quartiles of SUA was evident in both genders and across age groups. CONCLUSIONS: This study supports that high uric acid concentrations are associated with increased diabetes risk, independent of other known risk factors. These data expand on well-established associations between SUA level and metabolic syndrome, and extend the link to the future risk of type 2 diabetes.

Author Correction: Multiple gene promoter methylation and clinical stage in adjacent normal tissues: Effect on prognosis of colorectal cancer in Taiwan.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Novel methylation gene panel in adjacent normal tissues predicts poor prognosis of colorectal cancer in Taiwan.

BACKGROUND: It is evident that current clinical criteria are suboptimal to accurately estimate patient prognosis. Studies have identified epigenetic aberrant changes as novel prognostic factors for colorectal cancer (CRC). AIM: To estimate whether a methylation gene panel in different clinical stages can reflect a different prognosis. METHODS: We enrolled 120 CRC patients from Tri-Service General Hospital in Taiwan and used the candidate gene approach to select six genes involved in carcinogenesis pathways. Patients were divided into two groups based on the methylation status of the six evaluated genes, namely, the < 3 aberrancy group and ≥ 3 aberrancy group. Various tumor stages were divided into two subgroups (local and advanced stages) on the basis of the pathological type of the following tissues: Tumor and adjacent normal tissues (matched normal). We assessed DNA methylation in tumors and adjacent normal tissues from CRC patients and analyzed the association between DNA methylation with different cancer stages and the prognostic outcome including time to progression (TTP) and overall survival. RESULTS: We observed a significantly increasing trend of hazard ratio as the number of hypermethylated genes increased both in normal tissue and tumor tissue. The 5-year TTP survival curves showed a significant difference between the ≥ 3 aberrancy group and the < 3 aberrancy group. Compared with the < 3 aberrancy group, a significantly shorter TTP was observed in the ≥ 3 aberrancy group. We further analyzed the interaction between CRC prognosis and different cancer stages (local and advanced) according to the methylation status of the selected genes in both types of tissues. There was a significantly shorter 5-year TTP for tumors at advanced stages with the promoter methylation status of selected genes than for those with local stages. We found an interaction between cancer stages and the promoter methylation status of selected genes in both types of tissues. CONCLUSION: Our data provide a significant association between the methylation markers in normal tissues with advanced stage and prognosis of CRC. We recommend using these novel markers to assist in clinical decision-making.

Multiple gene promoter methylation and clinical stage in adjacent normal tissues: Effect on prognosis of colorectal cancer in Taiwan.

This study provide an insight that the panel genes methylation status in different clinical stage tended to reflect a different prognosis even in matched normal tissues, to clinical recommendation. We enrolled 153 colorectal cancer patients from a medical center in Taiwan and used the candidate gene approach to select five genes involved in carcinogenesis pathways. We analyzed the relationship between DNA methylation with different cancer stages and the prognostic outcome. There were significant trends of increasing risk of 5-year time to progression and event-free survival of subjects with raising number of hypermethylation genes both in normal tissue and tumor tissue. The group with two or more genes with aberrant methylation in the advanced cancer stages (Me/advanced) had lower 5-year event-free survival among patients with colorectal cancer in either normal or tumor tissue. The adjusted hazard ratios in the group with two or more genes with aberrant methylation with advanced cancer stages (Me/advanced) were 8.04 (95% CI, 2.80-23.1; P for trend <0.01) and 8.01 (95% CI, 1.92-33.4; P for trend <0.01) in normal and tumor tissue, respectively. DNA methylation status was significantly associated with poor prognosis outcome. This finding in the matched normal tissues of colorectal cancer patients could be an alternative source of prognostic markers to assist clinical decision making.

Utility of apolipoprotein measurements in predicting incident type 2 diabetes: A Chinese cohort study.

BACKGROUND/PURPOSE: There is conflicting data regarding the utility of measuring apolipoproteins in addition to traditional lipid measures in risk assessment of cardiometabolic diseases. The aim of this study was to determine whether apolipoprotein measurements can improve the ability to predict the future development of type 2 diabetes beyond what is possible based on traditional type 2 diabetes risk factors and clinical routine lipid measurements. METHODS: A total of 4,223 Chinese adults without diabetes were followed for a mean duration of 5.42 years. The hazard ratios (HRs) with 95% confidence intervals (CIs) derived from the Cox proportional hazards model were used to analyze the longitudinal associations of apolipoprotein B (apo B), apolipoprotein A-I (apo A-I), and the apo B/apo A-I ratio with the risk of type 2 diabetes. Further, the analysis of the area under receiver operating characteristics curves (AUC) was performed to test the predictive value of apolipoprotein measurements. RESULTS: After adjusting for potential confounders, the HRs of diabetes consistently showed an increasing trend across both the apo B and the apo B/apo A-I ratio quartiles (p for trend = 0.004). In analyses of AUC, the predictive ability for type 2 diabetes risk for the apo B and the apo B/apo A-I ratio was superior to that of routine lipid and lipoprotein measurements. CONCLUSION: Apolipoprotein measurements significantly predict diabetes risk in an Asian population. Furthermore, the predictive ability of apo B alone to detect diabetes was comparable with that of the apo B/apo A-I ratio and better than the routine lipid measurements.

Correlation between kidney transplantation and colorectal cancer in hemodialysis patients: A nationwide, retrospective, population-based cohort study.

BACKGROUND: Kidney transplantation (KT) correlates with an increased risk of developing several malignancies; however, the risk of colorectal cancer (CRC) after KT remains debatable and has been marginally explored. Hence, in this nationwide, retrospective, population-based cohort study, we aimed to examine the correlation between KT and CRC in a large-scale population-based Chinese cohort. METHODS: We identified a total of 3739 regular hemodialysis patients undergoing KT (exposed cohort) and 42,324 hemodialysis patients not undergoing KT (non-exposed cohort) between 2000 and 2008 from Taiwan's National Health Insurance Research Database (NHIRD). Both cohorts were followed up from January 1, 2000, to the date of CRC diagnosis, death, or the end of 2013. Using Kaplan-Meier method, we measured the cumulative incidence of CRC in each cohort. Furthermore, Cox proportional hazards models were used to compute hazards ratios (HRs) and 95% confidence intervals (CIs) to estimate the correlation between KT and CRC in hemodialysis patients. RESULTS: The Kaplan-Meier analysis revealed that the cumulative incidence of CRC was significantly higher in the exposed cohort than in the non-exposed cohort (log-rank test, P < 0.001). After adjusting for potential confounders, the exposed cohort exhibited a significantly increased risk of CRC compared with the non-exposed cohort (adjusted HR, 1.34; 95% CI, 1.11-1.62). CONCLUSIONS: Hemodialysis patients undergoing KT have a significantly higher risk of CRC than those not undergoing KT. Cancer should continue to be a primary focus of prevention during KT.