Air pollution and well-being in China

The data were collected and reorganised from NERI index of marketization of China's Provinces Report (2004-2013), Global Annual PM2.5 Grids from MODIS, MISR and SeaWiFS Aerosol Optical Depth (AOD) with GWR (1998 – 2016), China Statistical Yearbook (2004-2014), Procuratorial Yearbook of China (2004-2013). The data include the indicators of well-being, PM10, SO2, proportion of days with air quality reaching or exceeding level two, carbon emission intensity, degree of marketization, GDP per capita, urbanization, arrestment rate, prosecution rate, unemployment rate, eduction input, belong to municipalities, belong to central region, belong to western region, and belong to minority region. The year range for the data is from 2003 to 2013. It covers Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, Shandong, Beijing, Tianjin, Hebei, Liaoning, Jilin, Heilongjiang, Tibet, Chongqing, Hubei, Anhui, Jiangsu, Yunnan, Guizhou, Hunan, Jiangxi, Zhejiang, Fujian, Guangdong, and Guangxi

Exploring Strategies for High Dielectric Constant and Low Loss Polymer Dielectrics

Polymer dielectrics having high dielectric constant, high temperature capability, and low loss are attractive for a broad range of applications such as film capacitors, gate dielectrics, artificial muscles, and electrocaloric cooling. Unfortunately, it is generally observed that higher polarization or dielectric constant tends to cause significantly enhanced dielectric loss. It is therefore highly desired that the fundamental physics of all types of polarization and loss mechanisms be thoroughly understood for dielectric polymers. In this Perspective, we intend to explore advantages and disadvantages for different types of polarization. Among a number of approaches, dipolar polarization is promising for high dielectric constant and low loss polymer dielectrics, if the dipolar relaxation peak can be pushed to above the gigahertz range. In particular, dipolar glass, paraelectric, and relaxor ferroelectric polymers are discussed for the dipolar polarization approach

Synthesis and Unimolecular Micelles of Amphiphilic Dendrimer-like Star Polymer with Various Functional Surface Groups

We report the synthesis and functionalization of amphiphilic dendrimer-like star polymers (DLSPs) with a hydrophobic star-shaped poly(l-lactide) (PLLA) core and a hydrophilic poly(amidoamine) (PAMAM) dendron shell. First, carboxylic acid-functionalized PLLA star polymer was synthesized by ring-opening polymerization of l-lactide followed by functionalization with succinic anhydride. Second, 1-, 2-, and 3-generation PAMAM dendrons with a primary amine at the dendron root and benzyl ester protections at the periphery were prepared via a divergent method. By amide coupling between the carboxylic acid-terminated PLLA star polymer and six PAMAM dendrons, amphiphilic DLSPs were successfully synthesized. To enhance bioactivity and bioconjugation capability, the benzyl ester surface groups in these DLSPs were converted to carboxylic acid, primary amine, and triethylene glycol functional groups, respectively. Nuclear magnetic resonance spectroscopy and size-exclusion chromatography were used to confirm quantitative functionalization. These functional DLSPs exhibited a unique unimolecular micelle (14−28 nm) behavior in aqueous solution with a small amount of aggregation (205−344 nm), as studied by dynamic light scattering. In addition, they also exhibited large differences in thermal behaviors depending on the nature of different surface groups. Experimental results showed that these DLSPs had good solubility in aqueous solutions (ca. 10−25 mg/mL) and could greatly enhance the water solubility of hydrophobic drugs. Therefore, these amphiphilic DLSPs are promising candidates for controlled hydrophobic drug delivery

Ortho-Selective Nucleophilic Aromatic Substitution Reactions of Polyhaloanilines with Potassium/Sodium <i>O</i>-Ethyl Xanthate: A Convenient Access to Halogenated 2(3<i>H</i>)-Benzothiazolethiones

Polyhaloanilines bearing an ortho halogen atom undergo smooth nucleophilic aromatic substitution reactions with anionic sulfur nucleophiles at relatively mild temperatures (95−120 °C). These reactions are very efficient and highly ortho-selective. With potassium/sodium O-ethyl xanthate as a nucleophile, subsequent cyclization follows to afford halogenated 2(3H)-benzothiazolethiones (2-mercaptobenzothiazoles) in high yields

Lamellar to Inverted Hexagonal Mesophase Transition in DNA Complexes with Calamitic, Discotic, and Cubic Shaped Cationic Lipids

In this study, we report on the lipid tail molecular shape/size effect on the mesophase self-assembly behaviors of various cationic lipids complexed with double-stranded DNA. The molecular shape of the cationic lipids was tailored from rodlike (a cyanobiphenyl imidazolium salt) to discotic (a triphenylene imidazolium salt), and finally to cubic [a polyhedral oligomeric silsesquioxane (POSS) imidazolium salt]. An increase in the cross-sectional area of the hydrophobic tails with respect to the hydrophilic imidazolium head induced a negative spontaneous curvature of the cationic lipids. As a result, a morphological change from lamello-columnar ( ) phase for the DNA−cyanobiphenyl imidazolium salt (DNA−rod) and DNA−triphenylene imidazolium salt (DNA−disk) complexes to an inverted hexagonal columnar ( ) phase for the DNA−POSS imidazolium salt (DNA−cube) complex was observed. The DNA−rod complex had a typical smectic A (SmA) morphology, whereas the DNA−disk complex had a double lamello-columnar liquid crystalline phase. However, when the lipid tail changed to POSS, an morphology was achieved. These morphological changes were successfully characterized by X-ray diffraction and transmission electron microscopy. We expect that these liquid crystalline and crystalline DNA hybrid materials may become potential functional materials for various applications such as organic microelectronics and gene transfection

Hydrogen Bond-Assisted Supramolecular Self-Assembly of Doubly Discotic Supermolecules Based on Porphyrin and Triphenylene

Hydrogen bonding is a powerful driving force for the supramolecular self-assembly of discotic mesogens, and molecular shape also plays an important role in such systems. To study these effects, doubly discotic supermolecules have been synthesized by linking a meso-tetraphenylporphine-4,4′,4′′,4′′′-tetracarboxylic acid (Py) core with four triphenylenes (Tp) arms via either amide or ester bonds. The spacer length between the Py core and Tp disks was C6 and C10, and the alkyl arm length in the Tp disks was C5 and C12, respectively. Compared to the ester-linked Py(Tp)4 supermolecules, the amide-linked samples exhibited rich crystalline and liquid-crystalline phases, suggesting that the intracolumnar hydrogen-bonding among trans amide bonds was the primary driving force for the self-assembly. X-ray diffraction (XRD) was used to understand the supramolecular self-assembly of the amide-linked Py(Tp)4 doubly discotic supermolecules. When the spacer length was no shorter than or similar to the triphenylene alkyl arm length, a rectangular boardlike molecular shape was adopted and thus lamellar structures were obtained. When the spacer length was much shorter than the triphenylene alkyl arms, an ellipsoidal overall molecular shape resulted, and thus a regular columnar phase was obtained. From this study, we speculated that hydrogen-bond-induced microphase separation between moieties with different electron affinities in doubly discotic supermolecules may be useful for the practical applications of organic electronics

Epitranscriptomic Analysis of m6A Methylome in Rats after Lumbosacral Nerve Root Avulsion. Supplementary tables.

Alteration in m6A landscape after lumbosacral nerve root avulsion </p

Nanoscale Phase Separation in Mixed Poly(<i>tert</i>-butyl acrylate)/Polystyrene Brushes on Silica Nanoparticles under Equilibrium Melt Conditions

This communication reports on the study of microphase separation of well-defined mixed poly(tert-butyl acrylate) (PtBA)/polystyrene (PS) brushes on silica nanoparticles under equilibrium melt conditions. Mixed PtBA/PS brushes were synthesized from an asymmetric, difunctional initiator-terminated self-assembled monolayer by combining atom transfer radical polymerization and nitroxide-mediated radical polymerization. Two symmetric PtBA/PS mixed brush samples with different molecular weights were used in this study and were thermally annealed in vacuum at 150 °C. For the mixed brushes with number average molecular weights (Mn) of 24 200 g/mol for PtBA and 23 000 g/mol for PS, two glass transitions were observed in the differential scanning calorimetry analysis. Transmission electron microscopy study showed that the two grafted polymers underwent a lateral microphase separation, forming a random worm-like pattern with a feature size of ∼10 nm on the silica particle surfaces. In contrast, the mixed brushes with a Mn of 10 400 g/mol for PtBA and 11 900 g/mol for PS did not microphase separate. Although the mixed brushes are on curved substrates, this work provides results consistent with the theoretical prediction that symmetric mixed homopolymer brushes undergo lateral rather than vertical phase separation under equilibrium melt conditions

Photochemically Stable Fluorescent Heteroditopic Ligands for Zinc Ion

Photochemically stable fluorescent heteroditopic ligands (9 and 10) for zinc ion were prepared and studied. Two independent metal coordination-driven photophysical processes, chelation-enhanced fluorescence (CHEF) and internal (or intramolecular) charge transfer (ICT), were designed into our heteroditopic ligand framework. This strategy successfully relates three coordination states of a ligand, non-, mono-, and dicoordinated, to three fluorescence states, fluorescence OFF, ON at one wavelength, and ON at another wavelength. This ligand platform has provided chemical foundation for applications such as the quantification of zinc concentration over broad ranges (Zhang, L.; Clark, R. J.; Zhu, L. Chem.−Eur. J. 2008, 14, 2894−2903) and molecular logic functions (Zhang, L.; Whitfield, W. A.; Zhu, L. Chem. Commun. 2008, 1880−1882). The binding stoichiometries of dipicolylamino and 2,2′-bipyridyl, the two binding sites featured in heteroditopic ligands 7−10, were studied in acetonitrile using both Job’s method of continuous variation and isothermal titration calorimetry (ITC). The fluorescence enhancement of 7−10 upon the formation of monozinc complexes (defined as the fluorescence quantum yield ratio of monozinc complex and free ligand) is qualitatively related to the highest occupied molecular orbital (HOMO) energy levels of their fluorophores. This is consistent with our hypothesis on the thermodynamics of the coordination-driven photophysical processes embodied in the designed heteroditopic system, which was supported by cyclic voltammetry studies. In conclusion, compounds 9 and 10 not only possess better photochemical stability but also display a higher degree of fluorescence turn-on upon formation of monozinc complexes than their vinyl counterparts 7 and 8

Topology Controlled Supramolecular Self-Assembly of Octa Triphenylene-Substituted Polyhedral Oligomeric Silsesquioxane Hybrid Supermolecules

A series of liquid crystalline star supermolecules with polyhedral oligomeric silsesquioxane (POSS) as the central scaffold and eight triphenylenes (Tp) as the peripheral arms were synthesized via amidization reactions. The supermolecules were denoted as POSS(Tp)8. Six POSS(Tp)8 samples were prepared with two alkyl chain lengths in the Tp (C5 and C12) and three spacer lengths (C2, C6, and C10) between the POSS core and the Tp arms. Three samples with C5-Tp were amorphous because of too short alkyl chains in the Tp, while the other three samples with C12-Tp self-assembled into hierarchical liquid crystalline mesophases, as studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). When the spacer length was C2, a column-within-column super hexagonal columnar phase was observed, because the POSS core and the Tp arms were intimately coupled together. With increasing the spacer length to C6 and C10, respectively, the POSS core and Tp arms became gradually decoupled. Alternating POSS-Tp lamellar morphology with a rectangular columnar symmetry (by XRD) was observed by TEM for the POSS(Tp)8 sample with a C6-spacer. For the POSS(Tp)8 sample with a C10-spacer, an oblique columnar phase was determined by XRD, and inverted columnar morphology with four Tp columns forming a super column within the POSS/alkyl chain matrix was observed by TEM. This study suggested that molecular topology played an important role in the supramolecular self-assembly of star-shaped POSS(Tp)8 supermolecules