Craig-Type Möbius Aromaticity and Antiaromaticity in Dimetalla[10]annulenes: A Metal-Induced Yin-and-Yang Pair

Aromaticity, one of the most fundamental concepts in chemistry, can be classified as Hückel- and Möbius-type according to the electron count and topology. In comparison with numerous Hückel aromatics containing 4<i>n</i>+2 π-electrons, Möbius aromatics with 4<i>n</i> π-electrons, especially the Craig-type species are particularly limited. Herein we demonstrate that the recently synthesized dimetalla[10]­annulenes could be Möbius aromatic or antiaromatic although the organic prototype [10]­annulene is nonaromatic due to the nonplanarity caused by the steric repulsion of two CH groups, suggesting the first example of yin-and-yang pair with Craig-type Möbius (anti)­aromaticity. Further study suggests that the lithium atoms in dimetalla[10]­annulenes are not spectator cations but play an important role in the aromaticity switch of these species due to their bonding interaction with the diene moieties. Our findings highlight the magic power of metals in the achievement of Craig-type Möbius aromatics, thus opening an avenue to such novel aromatics

Craig-Type Möbius Aromaticity and Antiaromaticity in Dimetalla[10]annulenes: A Metal-Induced Yin-and-Yang Pair

Aromaticity, one of the most fundamental concepts in chemistry, can be classified as Hückel- and Möbius-type according to the electron count and topology. In comparison with numerous Hückel aromatics containing 4<i>n</i>+2 π-electrons, Möbius aromatics with 4<i>n</i> π-electrons, especially the Craig-type species are particularly limited. Herein we demonstrate that the recently synthesized dimetalla[10]­annulenes could be Möbius aromatic or antiaromatic although the organic prototype [10]­annulene is nonaromatic due to the nonplanarity caused by the steric repulsion of two CH groups, suggesting the first example of yin-and-yang pair with Craig-type Möbius (anti)­aromaticity. Further study suggests that the lithium atoms in dimetalla[10]­annulenes are not spectator cations but play an important role in the aromaticity switch of these species due to their bonding interaction with the diene moieties. Our findings highlight the magic power of metals in the achievement of Craig-type Möbius aromatics, thus opening an avenue to such novel aromatics

Additional file 1 of Corneal remodeling after SMILE for moderate and high myopia: short-term assessment of spatial changes in corneal volume and thickness

Supplementary Material

The Relationship between Parkinson Disease and Brain Tumor: A Meta-Analysis

<div><p>Objective</p><p>Epidemiological studies have investigated the association between Parkinson disease (PD) occurrence and the risk of brain tumors, while the results remain controversial. We performed a meta-analysis to clarify the exact relationship between PD and brain tumors.</p><p>Methods</p><p>A systematic literature search was conducted using PubMed, Embase, ScienceDirect and CBM (China Biology Medicine Disc) before February 2016. Eligible studies were those that reported risk estimates of brain tumors among patients with PD or vice versa. A random-effects model was used to calculate the pooled odds ratio (OR) of the outcomes. Subgroup analyses and sensitivity analysis were conducted to explore the potential sources of heterogeneity.</p><p>Results</p><p>In total, eight studies involving 329,276 participants met our inclusion criteria. The pooled OR was 1.51 (95%CI 1.21–1.89), indicating that PD carried a higher risk of brain tumor. Analyses by temporal relationship found that the occurrence of brain tumor was significantly higher after the diagnosis of PD (OR 1.55, 95% CI 1.18–2.05), but not statistically significant before PD diagnosis (OR 1.21, 95%CI 0.93–1.58). Subgroup analysis showed that gender differences, ethnicity differences and the characteristic of the tumor (benign or malignant) did not make much change in the association between brain tumor and PD.</p><p>Conclusions</p><p>Our meta-analysis collecting epidemiological studies suggested a positive association of PD with brain tumors, while the influence of anti-parkinson drugs and ascertainment bias could not be excluded. Further studies with larger sample size and more strict inclusion criteria should be conducted in the future.</p></div

PRISMA flow chart of literature searches and results.

<p>PRISMA flow chart of literature searches and results.</p

Characteristics of Individual Study in the Meta-analysis.

<p>Characteristics of Individual Study in the Meta-analysis.</p

Forest plot of ORs for risk of brain tumor among PD patients.

<p>(OR 1.51, 95%CI 1.21–1.89, p<0.001, heterogeneity <i>I</i>^<i>2</i> = 55.7%, p = 0.008) and subgrouped by PD diagnosis time (brain tumor risk before PD, after PD or co-occurrence).</p

Pooled estimation on the risk of brain tumor in PD patients by subgroup analysis.

<p>Pooled estimation on the risk of brain tumor in PD patients by subgroup analysis.</p

Surface Engineering of Quantum Dots for Remarkably High Detectivity Photodetectors

Ternary alloyed CdSe_<i>x</i>Te_1–<i>x</i> colloidal QDs trap-passivated by iodide-based ligands (TBAI) are developed as building blocks for UV–NIR photodetectors. Both the few surface traps and high loading of QDs are obtained by in situ ligand exchange with TBAI. The device is sensitive to a broad wavelength range covering the UV–NIR region (300–850 nm), showing an excellent photoresponsivity of 53 mA/W, a fast response time of ≪0.02s, and remarkably high detectivity values of 8 × 10¹³ Jones at 450 nm and 1 × 10¹³ Jones at 800 nm without an external bias voltage. Such performance is superior to what has been reported earlier for QD-based photodetectors. The photodetector exhibits excellent stability, keeping 98% of photoelectric responsivity after 2 months of illumination in air even without encapsulation. In addition, the semitransparent device is successfully fabricated using a Ag nanowires/polyimide transparent substrate. Such self-powered photodetectors with fast response speed and a stable, broad-band response are expected to function under a broad range of environmental conditions

Serum starvation enhances EGCG-induced cell death independent of caspase.

<p>(A) Serum deprivation promotes EGCG-induced cell death in a concentration-dependent and time-course manner. HepG2 cells were treated with different doses of EGCG in full or serum-free medium for 12 h (left panel) or with 60 µM EGCG for different time as indicated (right panel). The cell viability was determined by Hoechst-PI double staining (n = 3, mean ± SD). (B) Representative pictures of Hoechst-PI double staining. HepG2 cells were cultured in full medium (as a control); treated with 60 µM EGCG for 12 h in serum-free medium; or incubated with 20 ng/ml TNFα and 10 µg/ml CHX for 12 h in full medium (as a positive control for apoptosis). (C) EGCG induces caspase-independent cell death. HepG2 cells were treated with EGCG (60 µM×24 h) or in the absence or presence of 40 µM z-VAD-fmk. The co-treatment with TNFα (20 ng/ml) and CHX (10 µg/ml) for 12 h was used as a positive control. Cell viability was determined as described in Panel A. **<i>p</i><0.005 comparing to the group without z-VAD (Student's <i>t</i>-test, n = 3). (D) No caspase-3 activation and PARP cleavage cause by EGCG-induced cell death. Cells were treated with EGCG or TNF/CHX as described in panel C, and cell lysates were collected and subject to western blot.</p