Trifunctional pNHC, Imine, Pyridine Pincer-Type Iridium(III) Complexes: Synthetic, Structural, and Reactivity Studies

Iridium­(III) complexes with a trifunctional pincer ligand containing protic N-heterocyclic carbene (pNHC), pyridine, and imine donor groups were obtained in two sequential steps: (i) protonation of 2-(1-(2,6-diiso­propyl­phenyl­imino)­ethyl)-6-(1-imidazolyl)­pyridine (<b>L</b>^CH; the superscript specifies the position of the tautomerizable H atom in the imidazole ring) with HBF₄·Et₂O to give the imidazolium salt [H<b>L</b>^CH]⁺[BF₄]⁻ (protonation always occurs at the imidazole N atom) and (ii) metalation of the latter with [Ir­(cod)­(μ-Cl)]₂ to give the hydrido pincer complex [Ir­(H)­(Cl)­(NCMe)­{<b>L</b>^NH-κ³<i>N</i>_imine,<i>N</i>_Py,<i>C</i>_NHC}]⁺[BF₄]⁻ (<b>3</b>⁺[BF₄]⁻). Substitution of MeCN in <b>3</b>⁺[BF₄]⁻ by treatment with triiso­propyl­phosphine gave the analogue [Ir­(H)­(Cl)­P­(<i>i</i>-Pr)₃{<b>L</b>^NH-κ³<i>N</i>_imine,<i>N</i>_Py,<i>C</i>_NHC}]⁺[BF₄]⁻ (<b>4</b>⁺[BF₄]⁻). Chloride abstraction from <b>3</b>⁺[BF₄]⁻ by AgBF₄ gave [Ir­(H)­(NCMe)₂{<b>L</b>^NH-κ³<i>N</i>_imine,<i>N</i>_Py,<i>C</i>_NHC}]²⁺[BF₄^–]₂ (<b>5</b>²⁺[BF₄^–]₂). The centro­symmetric dinuclear Ir­(III) complex [Ir­(H)­(NCMe)­{μ-(<b>L</b>^CH−H)-κ³<i>N</i>_imine,<i>N</i>_Py,<i>C</i>2,κ<i>N</i>3}]₂²⁺[B­(C₆F₅)₃F^–]₂ (<b>6</b>²⁺[B­(C₆F₅)₃F^–]₂) was obtained after deprotonation of <b>5</b>²⁺[BF₄^–]₂ with KO-<i>t</i>-Bu, followed by addition of B­(C₆F₅)₃. It contains two Ir pincer moieties, each with a N_imine,N_Py,C2 donor set, which are connected by the Ir–N bonds involving the imidazolide rings, leading to a μ-C,N bridging mode for the latter. Remarkably, all of the donor atoms in the tetradentate bridging chelating ligands are chemically different. The molecular structures of <b>3</b>⁺[BF₄]⁻·CH₂Cl₂, <b>4</b>⁺[BF₄]⁻·CH₂Cl₂, <b>5</b>²⁺[BF₄^–]₂·2CH₂Cl₂, and <b>6</b>²⁺[B­(C₆F₅)₃F^–]₂·4CH₂Cl₂ have been determined by X-ray diffraction

Table_1_Association between acrylamide exposure and the odds of developmental disabilities in children: A cross-sectional study.docx

BackgroundThe association between acrylamide exposure and the odds of developmental disabilities (DDs) is unclear. We conducted this analysis to explore whether acrylamide exposure is related to DDs.MethodsWe analyzed a sample of 1,140 children aged 6–17 years old from the US National Health and Nutrition Examination Survey 2013–2014 to 2015–2016. DDs were determined by reports of parents. Acrylamide exposure was evaluated by the hemoglobin adducts of acrylamide (HbAA) and its major metabolite glycidamide (HbGA). We investigated the association using binomial logistic regression analysis by taking HbAA and HbGA as continuous or quartile variables. Restricted cubic splines (RCS) were used to explore the non-linear relationship between HbAA or HbGA and the odds of DDs. Interaction analysis and propensity score matching (PSM) were used to validate the results.ResultsA total of 134 participants were reported to have DDs. The median level of HbAA and HbGA was 41.6 and 40.5 pmol/g Hb, respectively. HbAA and HbGA were not associated with the odds of DDs when taken as continuous variables. When divided into quartiles, there was no evidence for a linear trend for HbAA and HbGA. RCS showed that there was a J-shaped association between HbGA and the odds of DDs (P for non-linearity, 0.023). The results were consistent in interaction analysis by age, gender, and race, and after PSM.ConclusionHbGA level was associated with the odds of DDs in a J-shaped manner among children. Further investigation is warranted to determine the causality and underlying mechanisms.</p

Quantum Chemistry Calculations on the Mechanism of Isoquinoline Ring-Opening and Denitrogenation in Supercritical Water

Computational studies at the M06/6-311G­(d,p) and M06-2<i>X</i>/6-311+G­(d,p) levels were performed to explore the detailed mechanism of isoquinoline ring-opening and denitrogenation in a supercritical water system. Three reaction paths with the same product, 2-(2-oxoethyl) benzaldehyde, were supported by the computational results. The rate-limiting step in the major degradation reaction is an addition reaction at the N position. H₂O is added to both the 1C–2N double bond (1C–2N addition reaction) and the 2N–3C double bond (2N–3C addition reaction) of the isoquinoline molecule, where the oxygen of H₂O is added to the carbon atom. The energy barrier of the 1C–2N addition reaction is 52.7 kcal/mol, while that of 2N–3C addition (from Path 6) is 60.1 kcal/mol. From catalysis by two water molecules, the barrier of 1C–2N addition (Reaction (1)) is reduced to 27.5 kcal/mol. Catalysis from water molecule clusters is shown to considerably affect the process of isoquinoline ring-opening and denitrogenation, as indicated by comparing the reaction energy barrier heights with and without water catalysts

Two novel ketone alkaloids from <i>Portulaca oleracea</i>L. and their anti-inflammatory activities

Eleven compounds were obtained from Portulaca oleracea L., including two novel ketone alkaloids, (1, 2), 4-hydroxy-3-methoxybenzamide (3) (isolated for the first time), β-adenosine (4), oleracrylimide A and B (5, 6), oleracein H, C, D, Q and A (7–11). The two novel ketone alkaloids were identified as 5-acetyl-5-methylcyclopent-2-ene-1-carboxamide (1), named oleraciamide H, and (2 R,3S,4R,5R)-5-((R)-1,2-dihydroxyethyl)-3,4-dihydroxytetrahydrofuran-2-yl glycinate (2), named oleracone Q by spectroscopic methods, including 1D, 2D NMR and compound fingerprints. Additionally, their anti-inflammatory activities were tested via RAW 264.7 cells induced by LPS and found that they could significantly inhibit the release of IL-1β and TNF-α.</p

Media 1: 3D flame topography obtained by tomographic chemiluminescence with direct comparison to planar Mie scattering measurements

Originally published in Applied Optics on 20 March 2015 (ao-54-9-2174

Risks of shigellosis by exposure in 85 cases and 71 controls in the school, Sichuan Province, China, 2009.

<p>NOTE.*Chi square for trend: χ² = 4.4, P = 0.035.</p

Epidemic curve.

<p>Epidemic curve for reported cases of Shigellosis by 1-day interval during a school outbreak, Sichuan Province, China, 2009.</p

Additional file 1 of Preoperative risk factors and cumulative incidence of temporary ileostomy non-closure after sphincter-preserving surgery for rectal cancer: a meta-analysis

Supplementary Material

Table_1_Quantitative assessment of lumbar spine bone marrow in patients with different severity of CKD by IDEAL-IQ magnetic resonance sequence.docx

BackgroundChronic kidney disease (CKD) has a significant negative impact on bone health. Bone marrow is an essential component of bone, mainly composed of trabecular bone and fat. The IDEAL-IQ sequence of MRI allows indirect quantification of trabecular bone mass by R2* and direct quantification of bone marrow fat content by FF map, respectively.ObjectiveOur objective was to explore the association of CKD severity with bone marrow using IDEAL-IQ and whether mineral and bone metabolism markers alter this association.MethodWe recruited 68 CKD patients in this cross-sectional research (15 with CKD stages 3-4, 26 with stage 5, and 27 with stage 5d). All patients underwent lumbar spine IDEAL-IQ, BMD, and several bone metabolism markers (iPTH, 25-(OH)-VitD, calcium and phosphorus). Multiple linear regression analysis was used to examine the association of CKD severity with MRI measurements (R2* and FF).ResultsMore severe CKD was associated with a higher R2* value [CKD 5d versus 3-4: 30.077 s-1 (95% CI: 12.937, 47.217), P for trend -1 (95% CI: 0.205, 39.114), P for trend = 0.042]. Furthermore, iPTH had an association with R2* value [iPTH (pg/mL): 0.033 s-1 (95% CI: 0.001, 0.064), P = 0.041]. Besides, FF was mainly affected by age and BMI, but not CKD.ConclusionsThe bone marrow R2* value measured by IDEAL-IQ sequence is associated with CKD severity and iPTH. The R2* of IDEAL-IQ has the potential to reflect lumbar bone changes in patients with CKD.</p

The Diagnosis Accuracy of PLA2R-AB in the Diagnosis of Idiopathic Membranous Nephropathy: A Meta-Analysis

<div><p>Background</p><p>The presence of antibodies against the M-type phospholipase A2 receptor (PLA2R-AB) is considered to be a promising serological diagnostic biomarker of idiopathic membranous nephropathy (iMN). However, controversy remains about the diagnostic accuracy of serum PLA2R-AB testing. Here, we performed a comprehensive meta-analysis to assess the overall diagnostic value of serum PLA2R-AB testing in iMN detection.</p><p>Methods</p><p>PubMed, Embase, and CNKI (Chinese National Knowledge Infrastructure) were searched for relevant original articles through January 31, 2014. The summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio (DOR) were estimated using the bivariate model. The heterogeneity among studies was explored by subgroup and meta-regression analysis.</p><p>Results</p><p>9 articles, including 15 studies, were eventually identified with a total of 2212 patients. The summary sensitivity of all studies is 78% (95% CI: 66% to 87%) and the specificity is 99% (95% CI: 96% to 100%). The summary positive and negative likelihood ratios are 96.1 (95% CI, 19.5 to 472.1) and 0.22 (95% CI: 0.14 to 0.35), respectively. The DOR is 437 (95%CI, 74 to 2592). The subgroup analysis and meta-regression suggest the test interval is the main source of heterogeneity.</p><p>Conclusions</p><p>Serum PLA2R-AB testing is a useful tool to detect iMN. In addition, considering the high heterogeneity and potential publication bias, further high quality studies are needed in the future.</p></div