Excited-State Modification of Phenylimidazole-Based Cyclometalated Ir(III) Complexes through Secondary Bulky Aryl Substitution and Inductive Modification Enhances the Blue Emission Efficiency in Phosphorescent OLEDs.

To elucidate the key parameters governing the emission properties of phenylimidazole (pim)-based Ir(III) emitters, including their electronic structure and the bulky aryl substitution effect, a series of pim-based iridium(III) complexes (Ir(Rpim-X)3, Rpim-X = 1-R-2-(X-phenyl)-1H-imidazole) bearing secondary pendants of increasing bulkiness [R = methyl (Me), phenyl (Ph), terphenyl (TPh), or 4-isopropyl terphenyl (ITPh)] and three different primary pim ligands (X = F, F2, and CN) were designed and synthesized. Based on photophysical and electrochemical analyses, it was found that the excited state properties are highly dependent on the bulkiness of the secondary substituent and the inductive nature of the primary pim ligand. The incorporation of bulky TPh/ITPh substituents in the second coordination sphere significantly enhanced the emission efficiencies in the solid state (ΦPL = 72.1-84.9%) compared to those of the methyl- or phenyl-substituted Ir(III) complexes (ΦPL = 30.4% for Ir(Mepim)3 and 63.7% for Ir(Phpim)3). Further modification of the secondary aryl substituent (Ir(TPhpim)3 → Ir(ITPhpim)3) through the incorporation of an isopropyl group and F substitution on the primary pim ligand (Ir(TPh/ITPhpim)3 → Ir(TPh/ITPhpim-F/F2)3) resulted in a slight decrease in the LUMO and a significant decrease in the HOMO energy levels, respectively; these energy level adjustments consequently amplified emission blue shifts, thereby enabling efficient blue electroluminescence in phosphorescent organic light-emitting diodes. Theoretical calculations revealed that the excited-state properties of pim-based Ir(III) complexes can be modulated by the nature of the peripheral substituent and the presence of an EWG substituent. Among the fabricated blue-emitting TPh/ITPh-substituted Ir(III) complexes, Ir(ITPhpim-F)3, Ir(TPhpim-F2)3, and Ir(ITPhpim-F2)3 were tested as blue-emitting dopants for blue phosphorescent OLEDs owing to their high solid radiative quantum yields (ΦPL = 75.9-84.9%). The Ir(ITPhpim-F)3-doped multilayer device displayed the best performance with a maximum external quantum efficiency of 21.0%, a maximum current efficiency of 43.6 cd/A, and CIE coordinates of 0.18 and 0.31.

Tuning the Photophysical Properties of Homoleptic Tris-Cyclometalated Ir(III) Complexes by Facile Modification of the Imidazo-Phenanthridine and Their Application to Phosphorescent Organic Light-Emitting Diodes.

To explore the excited-state electronic structure of the blue-emitting Ir(dmp)3 dopant material (dmp = 3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridine), which is notable for durable blue phosphorescent organic light-emitting diode (PhOLED), a series of homoleptic dmp-based Ir(III) complexes (DMP-R, tris[3-(2,6-dimethylphenyl)-7-R-imidazo[1,2-f]phenanthridin-12-yl-κC 12,κN 1]iridium, R = H, CH3, F, and CF3) were prepared by introducing an electron-donating group (EDG; -CH3) or an electron-withdrawing group (EWG; -F and -CF3) at the 7-position of the imidazo-phenanthridine ligand. The photophysical analysis demonstrated that the alteration from EDG to EWGs led to redshifted structureless emission profiles, which were correlated with variations in the 3MLCT/3ILCT ratio in the T1 excited state. From electrochemical studies and density functional theory calculations, it turned out that the excited-state nature of the dmp-based Ir(III) complexes was significantly affected by the inductive effect of the 7-substituent of the cyclometalating dmp ligand. As a result of the lowest unoccupied molecular orbital energy stabilization by the EWGs that suppressed the non-radiative pathway from the emissive triplet excited state to the 3 d-d state, the F- and CF3-modified Ir(dmp)3 complexes (DMP-F and DMP-CF 3 ) showed quantum yields of 27-30% in the solution state, which were at least 4- or 5-fold higher than those shown by DMP-H and DMP-CH 3 . A PhOLED device based on DMP-CF 3 [CIE chromaticity (0.17, 0.39)], which demonstrated a distinct 3MLCT characteristic, exhibited better electroluminescent efficiencies with an external quantum efficiency of 13.5% than that based on DMP-CH 3 .

Progress in research and development of Xanthoceras sorbifolia / 中国中药杂志

Xanthoceras sorbifolia, an excellent oil-rich woody species, has high comprehensive economic value in edible, medicinal, and ornamental fields. The chemical composition, pharmacological effect, and quality control of X. sorbifolia were introduced, and its development and application were reviewed in this study. As revealed by the previous research, the main chemical constituents of X. sorbifolia were triterpenoids, flavonoids, fatty acids, phenylpropanoids, steroids, phenolic acids, organic acids, etc. It possesses pharmacological effects, such as neuroprotection, bacteriostasis, anti-oxidation, anti-tumor, anti-inflammation, analgesia, anti-HIV, and anti-coagulation. X. sorbifolia is widely applied in medical, food, chemical industry, and other fields, and deserves in-depth research and development.

Pharmacokinetics and tissue distribution of 125I-Fc-G-CSF in rats / 国际药学研究杂志

Objective: To investigate the pharmacokinetics, tissue distribution and excretion characteristics of Fc- G- CSF (the fusion protein of Fc and granulocyte colony stimulating factor)in rats. Methods: Fc-G-CSF was labeled with 125I by the chloramine T method, and the content of 125I-Fc-G-CSF in each biological sample was determined by the trichloroacetic acid(TCA)precipitation method. Results: After a single subcutaneous injection of 125I-Fc-G-CSF 30 μg/kg, the AUC was(362.1±48.1)μg•h/L and the Cmax was(27.0±3.0)μg/L. Up to 36 hours of the drug administration, the drug exposure was highest in serum but lowest in brain. Up to 96 hours of the drug administration, the cumulative excretion rate through urine was about 57.5%, and the cumulative excretion rate through feces was about 23.5%. Conclusion: The blood concentration of 125I-Fc-G-CSF reached a peak after 12 h of the subcutaneous injection in rats, and the serum concentration was continuously higher than the concentrations in other tissues. The 125I-Fc-G-CSF excretion mainly adopted the urinary excretion.

Photophysical properties of structural isomers of homoleptic Ir-complexes derived from xylenyl-substituted N-heterocyclic carbene ligands.

The phosphorescence properties of fac-Ir(pmp)3, mer-Ir(pmp)3, fac-Ir(dmpmp)3 and mer-Ir(dmpmp)3 (where pmp = 3-methyl-1-phenyl-2,3-dihydro-1H-imidazo[4,5-b]pyridine and dmpmp = 1-(2',6'-dimethylbiphenyl-2-yl)-3-methyl-2,3-dihydro-1H-imidazo[4,5-b]pyridine) in CH2Cl2 were investigated. At 77 K, the fac-isomers showed blue emission with a vibronic structure, while the mer-isomers showed less structured emissions. At 300 K, all complexes showed broad and markedly red-shifted emission spectra compared to those at 77 K. The quantum yields of the Ir(dmpmp)3 isomers were very low, and their emission lifetimes were very short compared to those of Ir(pmp)3. In order to understand the large differences between the photodynamic properties of Ir(pmp)3 and Ir(dmpmp)3, we performed femtosecond time-resolved transient absorption (TA) spectroscopic measurements. The TA spectra of Ir(dmpmp)3 were almost the same as those of Ir(pmp)3 at a short delay time. However, Ir(dmpmp)3 showed a new broad TA band at around 720 nm with increasing delay time. The rise time of this band was ca. 10 ps for both isomers, and this may be attributed to the geometrical change in the excited state, which is associated with the steric hindrance of the bulky dimethylphenyl substituent. Actually, Ir(dmpmp)3 showed a strong rigidochromic shift in the emission spectra with varying temperature. To understand the molecular orbitals and the energy levels, theoretical calculations were performed using density functional theory. As a result, structural displacement takes place accompanied by the fast migration of localization of excited states via intraligand charge transfer.

Photoinduced electron and hole transfers in carbazole dendrimers with heteroleptic Ir-complex cores.

We synthesised carbazole (Cz) dendrimers with heteroleptic Ir-complex cores. Upon excitation of the carbazole (Cz) dendrons, the phosphorescence of the core Ir(iii) complex was quenched due to the photoinduced electron transfer (PET) process. The PET dynamics of the excited Cz-dendrons were investigated using the femtosecond time-resolved transient absorption technique. A broad transient absorption (TA) band attributed to the S1-Sn transition of the 1Cz*-dendron was observed at around 630 nm in the first generation Cz-dendrimer (G1). This TA band in the second-generation dendrimer (G2) decayed with a longer lifetime of 55.5 ps compared to that of G1 (9.8 ps), because G2 has a larger distance between the Cz-dendron and Ir-complex core than that of G1. The decay time of the free 1Cz*-dendron was 6.3 ns, and thus, the reduced decay time in Gn corresponds to the PET dynamics. As a result of the PET process, the Cz cationic radical species (Cz˙+) was observed at around 780 nm. Interestingly, when the core Ir-complex in the dendrimer was excited with a 400 nm pulse selectively, the TA band of Cz˙+ was also detected at around 780 nm. This may be due to the photoinduced hole transfer (PHT) from the highest occupied molecular orbital (HOMO) energy state of Cz to the lowest singly occupied molecular orbital (LSOMO) energy state of the excited Ir-complex. The oxidation potential of Cz is lower than that of the Ir-complex, indicating that the HOMO of the Cz-dendron is located at a higher energy state than that of the Ir-complex. To investigate the relative order of the energy states and their orbital shapes, we performed theoretical calculations using density functional theory. The TA spectra were globally deconvoluted to generate the decay-associated spectra (DAS), from which the species-associated spectra (SAS) were calculated. The SAS can distinguish the individual intermediate species participating in the PET and PHT processes. The analysed rate constants of SAS were consistent with the results determined by the TA decays.

Exploring the Key Genes and Pathways of Osteoarthritis in Knee Cartilage in a Rat Model Using Gene Expression Profiling

PURPOSE: To compare differentially expressed genes (DEGs) mediating osteoarthritis (OA) in knee cartilage and in normal knee cartilage in a rat model of OA and to identify their impact on molecular pathways associated with OA. MATERIALS AND METHODS: A gene expression profile was downloaded from the Gene Expression Omnibus database. Analysis of DEGs was carried out using GEO2R. Enrichment analyses were performed on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway using the Search Tool for the Retrieval of Interacting Genes database (http://www.string-db.org/). Subsequently, the regulatory interaction network of OA-associated genes was visualized using Cytoscape software (version 3.4.0; www.cytoscape.org). RESULTS: In the gene expression profile GSE103416, a total of 99 DEGs were identified. Among them, 76 DEGs (76.77%) were overexpressed, and the remaining 23 DEGs (23.23%) were underexpressed. GO and pathway enrichment analyses of target genes were performed. Using gene-gene interaction network analysis, relevant core genes, including MET, UBB, GNAI3, and GNA13, were shown to hold a potential relationship with the development of OA in cartilage. Using quantitative real-time PCR, the Gna13/cGMP-PKG signaling pathway was identified as a potential research target for therapy and for further understanding the development of OA. CONCLUSION: The results of the present study provide a comprehensive understanding of the roles of DEGs in knee cartilage in relation to the development of OA.

Synthesis of benzimidazole and benzothiazole derivatives as a sirtuins 2 inhibitor / 药学学报

A series of novel benzimidazole and benzothiazole derivatives were designed and synthesized as inhibitors of SIRT1-SIRT3. The target compounds were synthesized from potassium O-ethyldithiocarbonate through a three-step route. The structures of the obtained compounds were elucidated by 1H NMR and HR-MS. Of all compounds, six showed potent SIRT2-inhibitory activities with IC50 values ranging from 2.8 to 21.2 μmol·L-1. Among them, compound 10c displayed the most potent SIRT2-inhibitory activities (IC50 = 2.8 μmol·L-1), with more than 35-fold selectivity over SIRT1 and SIRT3 (IC50>100 μmol·L-1).

Effects of early rehabilitation therapy on patients with mechanical ventilation / 世界急诊医学杂志（英文）

BACKGROUND:For patients in intensive care unit (ICU), mechanical ventilation is an effective treatment to survive from acute illness and improve survival rates. However, long periods of bed rest and restricted physical activity can result in side effects. This study aimed to investigate the feasibility of early rehabilitation therapy in patients with mechanical ventilation. METHODS:A randomized controlled trial was carried out. Sixty patients, with tracheal intubation or tracheostomy more than 48 hours and less than 72 hours, were admitted to the ICU of the Affiliated Hospital of Medical College, Qingdao University, from May 2010 to May 2012. These patients were randomly divided into a rehabilitation group and a control group. In the rehabilitation group, rehabilitation therapy was performed twice daily, and the training time and intensity were adjusted according to the condition of the patients. Early rehabilitation therapy included heading up actively, transferring from the supine position to sitting position, sitting at the edge of the bed, sitting in chair, transferring from sitting to standing, and ambulating bedside. The patient's body mass index, days to first out of bed, duration of mechanical ventilation, length of ICU stay, APACHE Ⅱ score, highest FiO2, lowest PaO2/FiO2 and hospital mortality of patients were all compared between the rehabilitation group and the control group. The differences between the two groups were compared using Student's t test. RESULTS:There was no significant difference in body mass index, APACHE Ⅱ score, highest FiO2, lowest PaO2/FiO2 and hospital mortality between the rehabilitation group and the control group (P>0.05). Patients in the rehabilitation group had shorter days to first out of bed (3.8±1.2 d vs. 7.3±2.8 d; P=0.00), duration of mechanical ventilation (5.6±2.1 d vs. 12.7±4.1 d; P=0.005) and length of ICU stay (12.7±4.1 d vs. 15.2±4.5 d; P=0.01) compared with the control group. CONCLUSION:Early rehabilitation therapy was feasible and effective in improving the outcomes of patients with mechanical ventilation.

Outbreak of infections caused by Group A Streptococcus after modified radical mastectomy.

BACKGROUND: Eight infections occurred after modified radical mastectomies in a tertiary-care hospital. Group A streptococci (GAS) were isolated from three of the eight patients. METHODS: To control the outbreak, an epidemiologic investigation was conducted, and healthcare workers were screened for pathogens. Strains isolated from healthcare workers were compared with patient strains by emm typing. RESULTS: One surgeon attended one of the eight operations and observed the other seven. Streptococcus strains from the hands of this surgeon were identical to the patient strains. After the surgeon was suspended from duty and underwent eradication treatment, the outbreak was controlled. CONCLUSIONS: This outbreak of GAS infection is believed to have occurred by airborne transmission. Suspending patient care by healthcare workers who carry the causative GAS in a site(s) other than the respiratory tract for only the first 24 h they are receiving chemoprophylaxis may not be long enough. Sampling of the hands of healthcare workers during an investigation of nosocomial GAS infection is valuable.