The nonradiative decay mechanism of dinuclear iridium complexes: a density functional theory study.

Dinuclear metal complexes are a promising class of compounds applicable to photoluminescence and catalysis. However, an understanding of the mechanism of the nonradiative decay process of dinuclear metal complexes remains very limited. Herein, the mechanism of the nonradiative decay process of dinuclear iridium(III) complexes (D1 and D2) and their mononuclear iridium(III) complex (M1) is elucidated by using density functional theory (DFT). Our results reveal that the nonradiative decay process occurs on a weak Ir-N bond and therefore results in metal-centered triplet excited (3MC) states. The deactivation pathways connecting the Franck-Condon region and the minimum energy seam of crossing (MESX) were further identified to be the determining step, which is the thermal deactivation pathways of 3MLCT → TS → 3MC→ MESX. The smaller energy barrier from the T1 minimum to the MESX state for D1 (9.48 kcal mol-1) and D2 (8.64 kcal mol-1) relative to that for M1 (10.95 kcal mol-1) plays a key role in observed weak emissions of D1 and D2 in the red region compared to that of M1. Moreover, by introducing the electron-withdrawing Cl atom at the para- or meta-position of the 2-phenylpyrimidine (ppd) moiety, a large energy barrier between the 3MC state and the T1 minimum is obtained. Our work not only provides the possibility of the nonradiative decay process of dinuclear iridium(III) materials, but also paves a promising way for reducing the nonradiative process and developing saturated efficient red dinuclear iridium(III) materials for broader potential application.

Research on the Influence of Combustion Methods on NO x Emissions from Co-combustion of Various Tannery Wastes.

To further increase combustion efficiency and reduce nitrogen oxide pollution caused by tannery wastes, three raw materials, including tannery sludge, chrome-tanned buffing dust, and chrome shavings, were burned together in a dual-bed model reactor under various conditions. In addition, a thermogravimetric analysis of co-combustion of three tannery wastes was studied in this study, which was conducive to understanding the combustion characteristics and positive effects. The comprehensive combustibility index S, the flammability index K r, and the stable combustion characteristic index G b all increased when the tannery sludge was blended with chrome-tanned buffing dust and chrome shavings, indicating that the combustion behavior was improved by co-combustion. For normal combustion, decreasing the gas volume flow and temperature resulted in a decrease in the oxidation of nitrogen compounds, consequently lowering the NO x emission. During air staged combustion, at an appropriate secondary gas ratio of about 10-40%, the NO x reduction would be increased from 10.9 to 19.3%. By increasing the tertiary gas volume flow from 0.2 to 1.1 L/min in decoupling combustion, an average relative NO x reduction efficiency of 47% was attained compared with normal combustion. The results offered a viable technology that resulted in a lower NO x emission and realized the application of decoupling combustion.

Surgical resection of primary tumor is associated with prolonged survival in low-grade pancreatic neuroendocrine tumors.

INTRODUCTION: The incidence of pancreatic neuroendocrine tumors (PNETs) is increasing over the past few decades. Surgery for low-grade and small PNETs of less than 2cm and N0M0 is still debated. The purpose of this study is to examine the association between surgical resection and survival in patients with low-grade nonfunctioning PNETs. MATERIALS AND METHODS: Patients diagnosed with PNETs between 2004 and 2015 were extracted from SEER. Kaplan-Meier methods and Cox proportional hazard models were used to estimate independent predictors in PNETs patients. RESULTS: A total of 2637 patients (2147 underwent surgical resection and 490 did not undergo surgery) with histologically confirmed low-grade PNETs in this cohort study. Overall survival (OS) and cancer-specific survival (CSS) of patients with surgery was better than those without surgery (log rank test POS<0.001, PCSS<0.001). Multivariate Cox regression analysis showed that surgical status was an independent prognostic factor associated with OS (HR 3.257, 95%CI: 2.635, 4.026) and CSS (HR 3.546, 95%CI: 2.798, 4.493). Subgroup analysis suggested the patients receiving surgery apparently had better OS and CSS regardless of tumor size (all log rank test POS<0.001, all log rank test PCSS<0.001) and SEER stage (all log rank test POS<0.001, all log rank test PCSS<0.001), compared to patients without removal of the primary tumor. CONCLUSIONS: Surgical resection of primary tumor may have a significant benefit on survival for patients with low-grade nonfunctioning PNETs. To determine the optimal management, grade, stage and tumor size should be considered comprehensively.

Association of MAD1L1 polymorphism (rs871925) with prenatal famine exposure and schizophrenia in a Chinese population: A case-control study.

Schizophrenia (SCZ) is a complex, frequently disabling psychiatric disorder. Prenatal exposure to famine, an environmental factor, plays a significant role in the cause of SCZ. We used DNA methylation related sites to analyze their association with prenatal famine exposure and SCZ risk in a Northeast Han Chinese population. A total of 967 subjects (446 patients with SCZ/521 health controls) were recruited. Five single-nucleotide polymorphisms (rs2300149 in ITIH1, rs2675956 in NGEF, rs3758543 in NT5C2, rs7003288 in NA, and rs871925 in MAD1L1) were selected and genotyped. Genotype distribution and allele frequency analysis indicated that rs871925 was significantly associated with SCZ. We also found a significant association between prenatal exposure to famine and rs871925 in the recessive model in the health control group. The generalized multifactor dimensionality reduction analysis suggested a five-locus interaction model association with the risk of developing SCZ. Our data suggested that MAD1L1 rs871925 was associated with prenatal famine exposure and SCZ susceptibility in a Northeast Han Chinese population.

Fibrinogen and Kininogen are Potential Serum Protein Biomarkers for Depressive Disorder.

BACKGROUND: Depressive disorder is a debilitating psychiatric mental disease. However, no biological methods are used for the diagnosis of this disorder. Proteomic approaches for biomarker discovery may provide an important objective tool for diagnostics of depression. This study aimed to identify serum protein biomarkers for diagnosis of depressive disorder. METHODS: We screened for potential depression biomarkers in 175 serum samples from 86 patients and 89 healthy controls. Serum protein spectrums were detected by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Differentially expressed peptides among the two groups were analyzed and followed by sequence analysis to identify these peptides. RESULTS: Five peaks were found to have a significant different between the depression and healthy control groups. Among them, up-regulated m/z 1,466.21 and down-regulated m/z 1,944.99 are identified as the fractions of fibrinogen alpha chain and kininogen 1, respectively. CONCLUSIONS: Fibrinogen and kininogen may be potential serum protein biomarkers in the diagnosis and prognosis of depressive disorders.

Kininogen-1 as a protein biomarker for schizophrenia through mass spectrometry and genetic association analyses.

BACKGROUND: Schizophrenia (SCZ) is a complex and severe mental illness. There is a lack of effective biomarkers for SCZ diagnosis. The aim of this study was to explore the possibility of using serum peptides for the diagnosis of SCZ as well as analyze the association of variants in genes coding for these peptides and SCZ. METHODS: After bead-based fractionation, the matrix-assisted laser desorption ionization/time-of-flight mass spectrometry technique was used to identify peptides that showed different expressions between 166 SCZ patients and 201 healthy controls. Differentially expressed peptides were verified in a second set of samples (81 SCZ patients and 103 healthy controls). The association of SCZ and three tagSNPs selected in genes coding for differentially expressed peptides was performed in 1,126 SCZ patients and 1,168 controls. RESULTS: The expression level of peptides with m/z 1,945.07 was significant lower in SCZ patients than in healthy controls (P < 0.000001). The peptide with m/z 1,945.07 was confirmed to be a fragment of Kininogen-1. In the verification tests, Kininogen-1 had a sensitivity of 95.1% and a specificity of 97.1% in SCZ prediction. Among the three tagSNPs (rs13037490, rs2983639, rs2983640) selected in the Cystatin 9 gene (CST9) which encodes peptides including Kininogen-1, tagSNP rs2983640 had its genotype distributions significantly different between SCZ patients and controls under different genetic models (P < 0.05). Haplotypes CG (rs2983639-rs2983640) and TCG (rs13037490-rs2983639-rs2983640) were significantly associated with SCZ (CG: OR = 1.21, 95% CI [1.02-1.44], P = 0.032; TCG: OR = 24.85, 95% CI [5.98-103.17], P < 0.0001). CONCLUSIONS: The present study demonstrated that SCZ patients had decreased expression of Kininogen-1 and genetic variants in Kininogen-1 coding gene CST9 were significantly associated with SCZ. The findings from both protein and genetic association studies suggest that Kininogen-1 could be a biomarker of SCZ.

The Relationship between Gene Polymorphism of miRNAs Regulating FGA and Schizophrenia.

AIM: To investigate the relationship between the polymorphism of related gene loci of miRNAs regulated fibrinopeptide A and schizophrenia. Lay the foundation for the aetiology of schizophrenia. METHODS: Adapt to the phase match of sex and age case-control study, a total of 513 Chinese Han patients with schizophrenia were selected as the case group, 513 normal healthy persons as a control group. Obtaining SNPs information of the FGA gene by querying the dbSNP database, and reference HapMap database included SNPs site frequency information for screening. The frequency distributions of SNPs were genotyped by iMLDR® SNP detection technology. Two SNPs (pre-hsa-miR-605rs2043556 T>C, pre-hsa-miR-499a/pre-hsa-miR-499brs4909237 T < C) were analyzed to demonstrate their association with susceptibility to schizophrenia. RESULTS: There were no significant differences between patients and controls in genotype and allele distribution of SNPs rs2043556 and rs4909237 in the precursor region of hsa-miR-605 and pre-hsa-miR-499a/pre-hsa-miR-499b. Their gene-gene interaction, which suggests that the polymorphisms of miRNA genes might not contribute to schizophrenia susceptibility in the Han Chinese population. CONCLUSION: No significant difference existed between schizophrenic patients and controls in SNP (rs2043556 and rs4909237) in the precursor region of hsa-miR-605 and pre-hsa-miR-499a/pre-hsa-miR-499b. There may not regulate FGA gene expression. Thus, hsa-miR-605 and pre-hsa-miR-499a/pre-hsa-miR-499b may not influence the risks of schizophrenia.

CACNA1C Polymorphism (rs2283291) Is Associated with Schizophrenia in Chinese Males: A Case-Control Study.

Recent research has shown that prenatal famine exposure may be one of the risk factors for schizophrenia and that people born in famine years may be at an increased risk of schizophrenia due to alteration of the DNA methylation of genes. In this study, the association of rs2283291/rs4648635 and the incidence of schizophrenia and prenatal famine exposure at the genetic level were investigated to provide clues to the pathogenesis of schizophrenia. A total of 960 participants were recruited, comprising 473 prenatal famine-exposed individuals (225 patients and 248 controls) and 487 prenatal non-famine-exposed individuals (220 patients and 267 controls). The association of prenatal famine, schizophrenia, and their interaction with DNA methylation levels was analyzed using SPSS and GMDR software. Gender stratification analysis revealed a significant association between the rs2283291 genotype and schizophrenia in male patients (P = 0.017), and difference still existed after correction by the Bonferroni method. It was also found that an increasing risk of schizophrenia was associated with rs2283291 in males (OR: 1.62, 95% CI: 1.13-2.33, P = 0.0086, AIC = 669.7) in an overdominant model. The results of gene-environment interaction and gene-gene interaction revealed no association with the risk of schizophrenia. This study reported for the first time that rs2283291 was associated with schizophrenia in Chinese males.

The identification of active N species in N-doped carbon carriers that improve the activity of Fe electrocatalysts towards the oxygen evolution reaction.

Nitrogen-doped carbon nanomaterials have become some of the most effective carriers for transition metal-based electrocatalysts towards the oxygen evolution reaction. However, the specific active nitrogen species in nitrogen-doped carriers remains unclear up to now. To identify the active nitrogen species, herein, we prepare nitrogen-doped carbon nanospheres containing different types of nitrogen species and a small amount of Fe atoms. Electrochemical tests demonstrate that the Fe/nitrogen-doped carbon nanospheres with more graphitic nitrogen exhibit much higher activity for the oxygen evolution reaction than those with more pyridinic nitrogens and pyrrolic nitrogens in alkaline media, revealing that the graphitic nitrogen is the active species that greatly improves the activity of Fe catalysts. Density functional theory calculations further reveal that the graphitic nitrogen enhances the activity and stability of Fe-based catalysts mainly through increasing the adsorption energy, charge and spin densities of the Fe atoms loaded around it. These findings provide a brand-new perspective for rationally designing more effective transition metal-based electrocatalysts for the oxygen evolution reaction through controlling the active graphitic nitrogen distribution in carbon carriers.

Relationship of Gallbladder Diseases with Sociodemographic Characteristics, Lifestyle, and Chronic Diseases in Northeastern China.

BACKGROUND: Gallbladder diseases are common in Jilin, China. However, there have been few previous studies on this disease. Our study used the chronic disease database in Jilin Province to study the factors correlated with gallbladder diseases. METHODS: A total of 21,435 people were selected from the Jilin Province adult chronic disease survey conducted in 2012. Multistage stratified random cluster sampling was used in this cross-sectional study. Multiple logistic regression analysis was used to explore the independent associations of different factors with gallbladder diseases. RESULTS: There were 1876 people with gallbladder diseases, and the prevalence of the diseases was 8.8% (males 4.4%, females 12.8%). Multivariate logistic regression analysis showed that female (prevalence odds ratio (POR) = 3.13, 95% confidence intervals (CIs): 2.76⁻3.55), older people (30⁻45 years (POR = 2.79, 95% CIs: 2.06⁻3.77), 45⁻60 years (POR = 4.26, 95% CIs: 3.17⁻5.73), 60⁻79 years (POR = 4.72, 95% CIs: 3.48⁻6.41)), people living in rural areas (POR = 1.65, 95% CIs: 1.49⁻1.82), smoking (current smoker (POR = 1.15, 95% CIs: 1.01⁻1.31), former smoker (POR = 1.37, 95% CIs: 1.13⁻1.66)), high frequency of eating seafood (POR = 0.77, 95% CIs: 0.63⁻0.93), and high frequency of eating soy products (POR = 0.50, 95% CIs: 0.44⁻0.58) were associated with gallbladder diseases. CONCLUSIONS: We found that there were some factors associated with gallbladder disease, and there needs to be further studies to confirm these associations.

Association Between Polymorphisms of the Complement 3 Gene and Schizophrenia in a Han Chinese Population.

BACKGROUND/AIMS: Schizophrenia is a severe psychiatric disorder, and complement 3 (C3) is closely related to schizophrenia. We investigated the association between C3 polymorphisms and schizophrenia in a Northeast Han Chinese population. METHODS: A total of 2240 Chinese people, consisting of 1086 patients with schizophrenia and 1154 healthy controls, were recruited for this study. Ten single nucleotide polymorphisms (SNPs; rs11569562, rs344555, rs2241393, rs2241392, rs11569514, rs445750, rs451760, rs11672613, rs2230205, and rs2250656) in C3 were selected and genotyped. RESULTS: Genotype distribution analysis indicated that rs11569514 was significantly associated with schizophrenia. In the dominant model (AA vs. GG+GA genotypes), we found a significant protective effect for rs344555 against schizophrenia (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.53-0.99, P = 0.04). In the codominant model (TT vs. AA), we found a significant risk effect for rs11569514 on schizophrenia (OR: 4.39, 95% CI: 2.06-9.37, P < 0.001). Haplotypes, including TG (rs11569562 and rs344555), TGG (rs11569562-rs344555-rs2241393), AG (rs344555-rs2241393), CGGGT (rs11569562-rs344555-rs2241393-rs2241392-rs11569514), and ACGTG (rs11569514-rs445750-rs451760-rs11672613-rs2230205), showed either a risk or protective role for schizophrenia. CONCLUSIONS: SNP rs11569514 in C3 and haplotypes of C3 variants were associated with schizophrenia in a Han Chinese population.

Tuning the Geometrical Structures and Optical Properties of Blue-Emitting Iridium(III) Complexes through Dimethylamine Substitutions: A Theoretical Study.

The geometrical structures and photophysical properties of Ir(4,6-dFppy)2(pic) (FIrpic) and its derivative (o-FIr, m-FIr, p-FIr) with dimethylamine substituted at the picolinic acid (N∧O) ligand were fully investigated by density functional theory and time-dependent density functional theory. The simulated electronic structure, as well as absorption and emission spectra of FIrpic are in good agreement with the experimental observations. The introduction of dimethylamine at the N∧O ligand at different positions is beneficial to extend the π-electron delocalization, increase HOMO energy levels, and hence improve the hole injection and transfer ability compared with those of FIrpic. Furthermore, o-FIr, m-FIr, and p-FIr have large absorption intensity and participation of metal-to-ligand charge transfer (MLCT) contribution in the main absorption spectra, which would be useful to improve the intersystem crossing (ISC) from the singlet to triplet excited state. More importantly, the high quantum yield of o-FIr (which is explained based on the detailed analysis of triplet energy, ET1), participation of ³MLCT contribution in the phosphorescent spectra, and energy difference between ³MLCT and triplet metal centered (³MC) d-d excited state compared with m-FIr and p-FIr indicate that o-FIr is expected to be an excellent blue phosphorescence emitter with high efficiency.

Charge Transfer Enhancement in the D-π-A Type Porphyrin Dyes: A Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) Study.

The electronic geometries and optical properties of two D-π-A type zinc porphyrin dyes (NCH3-YD2 and TPhe-YD) were systematically investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to reveal the origin of significantly altered charge transfer enhancement by changing the electron donor of the famous porphyrin-based sensitizer YD2-o-C8. The molecular geometries and photophysical properties of dyes before and after binding to the TiO2 cluster were fully investigated. From the analyses of natural bond orbital (NBO), extended charge decomposition analysis (ECDA), and electron density variations (Δρ) between the excited state and ground state, it was found that the introduction of N(CH3)2 and 1,1,2-triphenylethene groups enhanced the intramolecular charge-transfer (ICT) character compared to YD2-o-C8. The absorption wavelength and transition possess character were significantly influenced by N(CH3)2 and 1,1,2-triphenylethene groups. NCH3-YD2 with N(CH3)2 groups in the donor part is an effective way to improve the interactions between the dyes and TiO2 surface, light having efficiency (LHE), and free energy change (ΔGinject), which is expected to be an efficient dye for use in dye-sensitized solar cells (DSSCs).

Triphenylamine-based indoline derivatives for dye-sensitized solar cells: a density functional theory investigation.

A new series of triphenylamine-based indoline dye sensitizers were molecularly designed and investigated for their potential use in dye-sensitized solar cells (DSSCs). Theoretical calculations revealed that modifying donor part of D149 by triphenylamine significantly altered the electronic structures, MO energies, and intramolecular charge transfer (ICT) absorption band. Key parameters associated with the light-harvesting efficiency at a given wavelength LHE(λ), the driving force ΔG inject, and the open-circuit photovoltage V oc were characterized. More importantly, these designed (dimeric) dye sensitizers were found to have similar broad absorption spectra to their corresponding monomers, indicating that modifying the donor part with triphenylamine may stop unfavorable dye aggregation. Further analyses of the dye-(TiO2)9 cluster interaction confirmed that there was strong electronic coupling at the interface. These results are expected to provide useful guidance in the molecular design of new highly efficient metal-free organic dyes.

Theoretical studies of the interactions of ethylene and formaldehyde with gold clusters.

We studied the adsorption of C(2)H(4) and CH(2)O on the gold clusters Au(n) (n = 1-5) in various adsorption modes using density functional theory PW91 functional. We found that the binding energies of pi-C(2)H(4) and pi and O-sigma modes of CH(2)O increase first and then decrease with the cluster size. Natural bonding orbital (NBO) analyses reveal that the donor-acceptor interaction plays an important role in these adsorption complexes and there is a nice linear relationship between the calculated binding energy and the stabilization energy estimated with second-order perturbation theory in the framework of NBO analysis. It is demonstrated that the bonding interaction between adsorbates and clusters follows the di-sigma > pi > O-sigma mode. However, due to adsorption induced structural deformation of adsorbates and clusters, the binding energies of different adsorption modes are comparable. It is shown that C(2)H(4) interacts more strongly with the clusters than CH(2)O does and that the previously assigned adsorption mode of C(2)H(4) on Au/MgO may not be the pi modes, but the C-sigma configuration.

A theoretical study of the effects of the charge state and size of gold clusters on the adsorption and dissociation of H2.

The adsorption and dissociation of H(2) on the neutral and charged gold clusters Au(n) (m)(m=0,+/-1; n=1-6) is investigated using the density functional theory PW91 functional. H(2) interacts very weakly with Au(n) (-1), whereas the interaction with Au(n) (+1) is relatively strong. The binding energies on neutral clusters are between those on the cationic and anionic systems. The binding energy decreases monotonically with the size increase of the cationic clusters while it goes up first and then goes down on the neutral systems with the maximum value of 0.78 eV at Au(3). Au cations show no propensity for the dissociation barrier reduction and are thermodynamically unfavorable for the dissociation. For the first time we find that H(2) dissociation involves valley-ridge inflection points on some clusters. Our results indicate that H(2) dissociates facilely at low temperatures on both neutral and cationic Au(4) and Au(5). The phenomenon that H(2) dissociation was not observed experimentally is not due to the higher dissociation barrier and weak binding of H(2). We also show that the coordination number of the Au atom may not play a determining role in H(2) dissociation.