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Urophysa is a Chinese endemic genus with only two species (U. rockii and U. henryi) distributed in Yungui Plateau (Guizhou Province) and adjacent regions (i.e., Provinces of Hunan, Hubei, Chongqing and Sichuan). The aim of this study was to determine the genetic diversity and population differentiation within Urophysa and investigate the effect of the Yungui Plateau uplift and climate oscillations on evolution of Urophysa. In this study, micro-morphological characteristics, nine microsatellite loci (SSR), two nuclear loci (ITS and ETS) and two chloroplast fragments (psbA-trnH and trnL-trnF) were used to analyze the phylogenetic relationships and assess genetic and phylogeographical structure of Urophysa. Isolation by distance (IBD) was performed to research the effects of geographical isolation. We detected high genetic diversity at the species level but low genetic diversity within populations. Striking genetic differentiation (AMOVA) among populations and a significant phylogeographical structure (NST > GST, p < 0.01) were detected among U. henryi populations, along with significant effects of isolation by distance (IBD). Molecular clock estimation using calibration strategy and cpDNA substitution rate indicated that the divergence of U. henryi occurred during late Miocene to early Quaternary, when the orogeny of Yungui Plateau was violent. U. rockii originated at the early Quaternary and further differentiated at early Pleistocene. Our results suggested that habitat fragmentation played an important role in the genetic diversity and population differentiation of U. rockii and U. henryi. Heterogenous geomorphological configuration and complicated environment resulted from rapid uplift of the Yungui Plateau were inferred as important incentives for the modern phylogeograhpical pattern and species divergence of Urophysa. The geographical isolation, limited gene flow, specialized morphologies and the Pleistocene climatic oscillation greatly contributed to the allopatric divergence of U. rockii. Significant genetic drift and inbreeding were detected in these two species, in situ measures should be implemented to protect them. [ABSTRACT FROM AUTHOR]

A series of 2-[(9 H-fluoren-2-yl)aryl]-1 H-benzo[ d]imidazoles 11-13 and 2,7-bis[(1 H-benzo[ d]imidazol-2-yl)aryl]-9 H-fluorenes 14-16 containing different linking aromatic units were synthesized in good yields. Their absorption and fluorescence properties were investigated in solution and in the solid state. Most compounds possess good fluorescence-emitting ability with φFL values in the region of 0.31-0.99 in solution and display strong blue emission. Structure-optical behavior characteristics and further details of the electronic properties from cyclic voltammetry measurements and theoretical calculations are discussed. [ABSTRACT FROM AUTHOR]

The respective roles that the Hengduan Mountains Region (HMR) uplift around 4–3 Ma and Quaternary climatic oscillations played in causing the environmental changes in the Qinghai-Tibet Plateau (QTP) remain unknown. Here, we reconstruct the evolutionary history of two varieties of Allium cyathophorum and A . spicatum of subgenus Cyathophora , restricted to the HMR and the western QTP, respectively. Forty-five populations were surveyed for chloroplast and nuclear sequence variation to evaluate phylogenetic relationships, dates of divergence and ancestral area/inflorescence reconstructions. In addition, analyses were conducted on discernable micromorphologies, cytotypes and seed size variation. Our results indicated that two varieties of A . cyathophorum are separate species, i.e. A . farreri and A . cyathophorum , and the initial split of Cyathophora was triggered by the HMR uplift around 4–3 Ma. Subsequently, A . spicatum originated through the strengthened aridification in the western QTP induced vicariance of the ancestral populations in the HMR during the early Pleistocene. A self-sustaining allotetraploid species from A . farreri and A . cyathophorum was established during an interglacial period of penultimate glaciation of the QTP. Seed size variation also supports these by the colonization-competition tradeoff among small and large seeds. Our findings appear to suggest that the HMR uplift could have strengthened the development of the Asian monsoon regimes in this region and aridification in the western QTP, while the Quaternary climatic oscillations spurred the allopatric species’ range shifts and created new open microhabitat for the alloploid species. [ABSTRACT FROM AUTHOR]

Abstract: A series of 2,3-diphenyl-10H-indeno[1,2-g]quinoxaline, 15H-dibenzo[a,c]indeno[1,2-i]phenazine, and 15H-indeno[1,2-i]phenanthro[4,5-abc]phenazine derivatives containing different terminal aromatic units such as phenyl, phenylethynyl, naphthyl, anthryl, pyrenyl, or 4-(diphenylamino)phenyl have been synthesized by employing palladium-catalyzed C–C cross-coupling reactions in good yields. All of the target compounds were characterized using 1H NMR, 13C NMR, high resolution MS, optical absorption, and emission spectra. Even though the electronic absorption spectra of the compounds were influenced by the nature of the peripheral arenes, the emission spectra indicated close similarity for the excited states in the 15H-indeno[1,2-i]phenanthro[4,5-abc]phenazine series compounds. Most compounds possess a medium fluorescence-emitting ability with φ FL values in the region of 0.40–0.71 and displayed blue, green, yellow, or red emission depending on the nature of the whole molecule. Structure–optical behavior characteristics and further details of the electronic properties from cyclic voltammetry measurements and theoretical calculations were discussed. [Copyright &y& Elsevier]

Abstract: Three new ternary potassium(I) zinc(II) or cadmium(II) tellurides, namely, K2Cd2Te3, K6CdTe4 and K2ZnTe2, were synthesized by solid-state reactions of the mixture of pure elements of K, Cd (or Zn) and Te in Nb tubes at high temperature. K2Cd2Te3 belongs to a new structure type and its structure contains a novel two-dimensional [Cd2Te3]2− layers perpendicular to the b-axis. K(5) cation is located at the center of five member rings of the 2D [Cd2Te3]2− layer, whereas other K+ cations occupy the interlayer space. K6CdTe4 with a K6HgS4 type structure features a “zero-dimensional” structure composed of isolated CdTe4 tetrahedra separated by the K+ ions. K2ZnTe2 in the K2ZnO2 structural type displays 1D [ZnTe2]2− anionic chains of edge sharing [ZnTe4] tetrahedra separated by the potassium(I) ions. K2Cd2Te3, K6CdTe4 and K2ZnTe2 revealed a band gap of 1.93, 2.51 and 3.0eV, respectively. [Copyright &y& Elsevier]

Abstract: Radical-scavenging antioxidants play vital roles in the prevention of oxidative damage caused by free radicals, which is involved in many important chemical and biological processes. Using the ONIOM-G3B3 method, the bond dissociation enthalpies (BDEs) of coenzyme Q, flavonoids, olives, curcumins, indolinonic hydroxylamines, phenothiazines, edaravones and antioxidants used as food additives are predicted in the present study. On the basis of the computed BDE values, discussions were then made about their antioxidant activities, structure–activity relationships, and radical scavenging mechanisms. This work may be useful to clarify the radical scavenging mechanism of antioxidants and to design novel antioxidants. [Copyright &y& Elsevier]

The roles of ribonucleoside and deoxyribonucleoside radicals in DNA and RNA damage cannot be properly understood in the absence of knowledge of the C−H and N−H bond dissociation enthalpies (BDEs) depicting the energy cost to generate each of these radicals. However, because the nucleoside radicals tend to be extremely short-lived and it is very difficult to separate and identify different nucleoside radicals, experimental BDEs for nucleosides have remained elusive. Herein, we developed an ONIOM-G3B3 method in order to reliably predict the BDEs of nucleosides and we carefully benchmarked this new method against over 60 experimental BDEs of diverse sizable molecules. It was found that the accuracy of the ONIOM-G3B3 method was about 1.4 kcal/mol for BDE calculations. Using the ONIOM-G3B3 method, a full scale of C−H and N−H BDEs were obtained for the first time for ribonucleosides and deoxyribonucleosides with an estimated error bar of ±1.4 kcal/mol. Discussions were then made about the interesting connections between these BDE values and previously reported experimental observations concerning radical-mediated DNA and RNA lesions. The significance of the work is twofold: (i) Nucleosides represent one of the most important groups of compounds in science. A full scale of reliable bond dissociation enthalpies for nucleosides is of fundamental importance. (ii) This work demonstrates the feasibility to accurately predict the bond strength of various sizable molecules ranging from nanosize molecular devices to biologically significant compounds. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the topological molecular descriptors were introduced to the QSAR studies of three types of 20(S)-camptothecin analogues and good relationships between the biological activity and the descriptors of the substitutions of those compounds were obtained with multiple regression. These QSAR models have good predictive ability, which will be of great benefit to our future design and synthesis of novel highly potent antitumor camptothecin analogues and be helpful for proving or improving the action mechanism supposed. [Copyright &y& Elsevier]

Multi‐component MOFs contain multiple sets of unique and hierarchical pores, with different functions for different applications, distributed in their inter‐linked domains. Herein, we report the construction of a class of precisely aligned flexible‐on‐rigid hybrid‐phase MOFs with a unique rods‐on‐octahedron morphology. We demonstrated that hybrid‐phase MOFs can be constructed based on two prerequisites: the partially matched topology at the interface of the two frameworks, and the structural flexibility of MOFs with acs topology, which can compensate for the differences in lattice parameters. Furthermore, we achieved domain selective loading of multiple guest molecules into the hybrid‐phase MOF, as observed by scanning transmission electron microscopy–energy‐dispersive X‐ray spectrometry elemental mapping. Most importantly, we successfully applied the constructed hybrid‐phase MOF to develop a dual‐drug delivery system with controllable loading ratio and release kinetics. [ABSTRACT FROM AUTHOR]

Multi‐component MOFs contain multiple sets of unique and hierarchical pores, with different functions for different applications, distributed in their inter‐linked domains. Herein, we report the construction of a class of precisely aligned flexible‐on‐rigid hybrid‐phase MOFs with a unique rods‐on‐octahedron morphology. We demonstrated that hybrid‐phase MOFs can be constructed based on two prerequisites: the partially matched topology at the interface of the two frameworks, and the structural flexibility of MOFs with acs topology, which can compensate for the differences in lattice parameters. Furthermore, we achieved domain selective loading of multiple guest molecules into the hybrid‐phase MOF, as observed by scanning transmission electron microscopy–energy‐dispersive X‐ray spectrometry elemental mapping. Most importantly, we successfully applied the constructed hybrid‐phase MOF to develop a dual‐drug delivery system with controllable loading ratio and release kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Two new ternary ytterbium transition metal stannides, namely, Yb3CoSn6 and Yb4Mn2Sn5, have been obtained by solid-state reactions of the corresponding pure elements in welded tantalum tubes at high temperature. Their crystal structures have been established by single-crystal X-ray diffraction studies. Yb3CoSn6 crystallizes in the orthorhombic space group Cmcm (no. 63) with cell parameters of a=4.662(2), b=15.964(6), c=13.140(5)Å, V=978.0(6)Å3, and Z=4. Its structure features a three-dimensional (3D) open-framework composed of unusual [CoSn3] layers interconnected by zigzag Sn chains, forming large tunnels along the c-axis which are occupied by the ytterbium cations. Yb4Mn2Sn5 is monoclinic space group C2/m (no. 12) with cell parameters of a=16.937(2), b=4.5949(3), c=7.6489(7)Å, β=106.176(4)°, V=571.70(8)Å3, and Z=2. It belongs to the Mg5Si6 structure type and its anionic substructure is composed of parallel [Mn2Sn2] ladders interconnected by unusual zigzag [Sn3] chains, forming large tunnels along the c-axis, which are filled by the ytterbium cations. Band structure calculations based on density function theory methods were also made for both compounds. [Copyright &y& Elsevier]

The clinical application of antitumor immunotherapy still faces severe challenges related to efficacy. Here, a light‐triggered core–shell nanosystem is designed to boost antitumor immune response via controlled release of anti‐PD‐L1 (αPD‐L1) antibodies and enhanced antigen presentation. The nanosystem (AZ‐P@P) is constructed via integrating gold nanorods (AuNRs) as a photothermal core and zeolitic imidazolate framework‐8 (ZIF‐8) as a shell for aPD‐L1 delivery, and further PEGylating. In the nanosystem, the ZIF‐8 shell protects αPD‐L1 antibody from the complex physiological environment and hyperthermia. Once accumulated at the tumor site, AZ‐P@P under near‐infrared (NIR) light‐triggered heating induces tumor cell deaths releasing tumor‐derived protein antigens (TDPAs) and adenosine triphosphate (ATP). Thereafter, the released ATP degrades the ZIF‐8 shell to expose the AuNRs, which can promote intratumoral T cell infiltration by capturing TDPAs and transporting them to dendritic cells (DCs). Concurrently, a large amount of αPD‐L1 is released in situ to reinvigorate T cell activity. Mechanistic studies reveal that AZ‐P@P promotes the maturation of DCs and the infiltration of activated T cells, thus eliciting a robust antitumor immunity. It is demonstrated that AZ‐P@P triggered by NIR light can significantly destroy primary tumors and suppress metastasis. This multiple immunoregulatory system provides a promising tool for tumor treatment. [ABSTRACT FROM AUTHOR]

Fluorescent materials exhibiting two‐photon induction (TPI) are used for nonlinear optics, bioimaging, and phototherapy. Polymerizations of molecular chromophores to form π‐conjugated structures were hindered by the lack of long‐range ordering in the structure and strong π–π stacking between the chromophores. Reported here is the rational design of a benzothiadiazole‐based covalent organic framework (COF) for promoting TPI and obtaining efficient two‐photon induced fluorescence emissions. Characterization and spectroscopic data revealed that the enhancement in TPI performance is attributed to the donor‐π‐acceptor‐π‐donor configuration and regular intervals of the chromophores, the large π‐conjugation domain, and the long‐range order of COF crystals. The crystalline structure of TPI‐COF attenuates the π–π stacking interactions between the layers, and overcomes aggregation‐caused emission quenching of the chromophores for improving near‐infrared two‐photon induced fluorescence imaging. [ABSTRACT FROM AUTHOR]

Fluorescent materials exhibiting two‐photon induction (TPI) are used for nonlinear optics, bioimaging, and phototherapy. Polymerizations of molecular chromophores to form π‐conjugated structures were hindered by the lack of long‐range ordering in the structure and strong π–π stacking between the chromophores. Reported here is the rational design of a benzothiadiazole‐based covalent organic framework (COF) for promoting TPI and obtaining efficient two‐photon induced fluorescence emissions. Characterization and spectroscopic data revealed that the enhancement in TPI performance is attributed to the donor‐π‐acceptor‐π‐donor configuration and regular intervals of the chromophores, the large π‐conjugation domain, and the long‐range order of COF crystals. The crystalline structure of TPI‐COF attenuates the π–π stacking interactions between the layers, and overcomes aggregation‐caused emission quenching of the chromophores for improving near‐infrared two‐photon induced fluorescence imaging. [ABSTRACT FROM AUTHOR]

• Participants were injected with a single booster doses 2–32 years after the primary immunization. • Participants were randomly divided into two groups receiving a booster dose of HepB (SC) or CHO. • Both linear and logistic regression models were used to detect the factors which were associated with immune response to a booster vaccination. To assess the immune effect of different types of hepatitis B vaccine (HepB) booster doses 2–32 years after primary immunization, explore the influencing factors, and offer guidance regarding the necessity and timing of boosters. In total, 1163 participants who were born from 1986 to 2015, received the HepB full-course primary vaccination, were hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) negative, and had hepatitis B surface antibody (anti-HBs) <10 mIU/mL were enrolled. Individuals were randomly divided into two groups and received a booster dose of HepB. Venous blood samples were collected 30 days later and tested for anti-HBs. In total, 595 and 568 individuals received a single dose of HepB (CHO) and HepB (SC), respectively. Venous blood samples were obtained from 1079 vaccinees (CHO: 554, SC: 525). The seroconversion rates were 93.68% (519/554) and 86.67% (455/525) (p < 0.05), with geometric mean concentrations (GMCs) of 426.58 mIU/ml and 223.8 mIU/ml, respectively. This result indicated that BMI, smoking status, vaccine types of booster and prebooster anti-HBs concentration significantly influenced anti-HBs levels. Only BMI, prebooster anti-HBs concentrations and booster types were different between the anti-HBs positive and negative groups. Participants boostered with HepB (CHO) had a relatively higher seroconversion rate than those boostered with HepB (SC). The high seroconversion rates in the two groups suggested that the subjects remained protected despite low circulating antibodies, so there is currently no urgent need for booster immunization. Factors including BMI ≥ 25 and prebooster anti-HBs concentration <2.5 mIU/mL, which contributed to lower responses to a booster dose, might indicate a greater risk of breakthrough infection. [ABSTRACT FROM AUTHOR]

Coal occupies a large proportion in the application of fossil energy and dominates the lifeblood of China's national economy. Coal spontaneous combustion (CSC), as one of the disasters in goaf of coal mines underground, could result in the coal fires, gas explosions or dust explosions, which threatens the workers and apparatus underground. Aiming to accurately explore the CSC characteristics of residual coal in goaf underground to prewarn the stages of CSC, a novel uniaxial compression equipped with a temperature-programmed(UCTP) device was built to carry out the fluid-solid-thermal-mechanical coupling tests. Based on the catastrophe theory, a new method for predicting the development stage of CSC is put forward. The following results were obtained: (i) The gas concentration, oxygen consumption rate and porosity are overall decreased as the stress increases. (ii) The kinetic parameters of coal oxidation loaded at 6.3 MPa recorded the highest results. (iii) The catastrophic temperature T C O is the optimal method to predict the development stage of CSC. (iv) Catastrophic temperature could characterize the CSC tendency, which appears under uniaxial stresses as follows: 2 MPa < 8 MPa <4 MPa < 0 MPa <6 MPa. The findings could provide the important theoretical guidance and technical support for the prediction of the process of CSC. [Display omitted] • The oxidation kinetics of coal are affected differently as the stress increasing. • A new research method for heating coal has been developed. • The traditional method of predicting CSC is optimized by catastrophe-theory method. • Carbon monoxide (CO) concentration is the most effective index-gas to predict the CSC stages. • Fracture volumes and stress states are the key factors affecting CSC at various buried depth. [ABSTRACT FROM AUTHOR]

[Display omitted] • The characteristics of CSC are mainly affected by particle size and stress. • The change in permeability is the root cause of the thermal hysteresis for CSC. • The stress field could affect the characteristics of CSC during coal mining. During coal-mining processes underground, the coal spontaneous combustion caused by air leakage of narrow coal pillars and residual coal in goaf under pressure not only threatens the safety of mining of coal resources, but also leads to serious casualties. Therefore, the research of multi-field coupling for broken coal could be helpful to reveal the spontaneous combustion law of narrow coal pillars and residual coal in goaf and find the key for coal-fire prevention and control. Therefore, the uniaxial compression equipped with a temperature-programmed device is applied to conduct stress-heating tests on five types of coal particle sizes. Moreover, based on the Hertz contact deformation principle under the three-particle model, the thermodynamic hysteresis characteristics of broken coal under uniaxial stresses are theoretically analyzed. The results are shown as follows: (i) Uniaxial stress leads to significant hysteresis effects on the critical temperature of coal spontaneous combustion, heating rate, Graham's Ratio-R 2 temperature coefficient and pyrolysis temperature. (ii) As the particle radius increases, the growth rate of the exothermic intensity is suppressed, while it has no inhibitory effect on the critical temperature of the minimum exothermic intensity. (iii) The extreme point for the limit parameter of coal spontaneous combustion and the critical temperature shows the same corresponding hysteresis under uniaxial stress. The particle size ratio changes the limit parameter of coal spontaneous combustion obviously, and coal with a large particle size would reduce the risk of spontaneous combustion. (iv) The stress–strain curves and the stress-porosity curves are divided into stages, and it is found that the critical uniaxial stress of the porosity and strain of each coal sample is up to 4 MPa. Moreover, the temperature is the main reason for the hysteresis of permeability. The stress sensitivity of permeability declines with the effective stress rising, increases with the temperature going up, and decreases with the coal particle size reducing. (v) The hysteresis effect of uniaxial stress on coal spontaneous combustion first increases, then decreases, and finally increases. [ABSTRACT FROM AUTHOR]

A new Schiff-base with two stereogenic centers has been prepared and its titanium complex applied to catalyze the pinacol coupling of aldehydes, which afforded pinacols in high yield, excellent diastereoselectivities, and high enantioselectivities. [Copyright &y& Elsevier]

Rücktitelbild: Covalent Organic Framework for Improving Near-Infrared Light Induced Fluorescence Imaging through Two-Photon Induction (Angew. Keywords: Fluoreszenz; Kontrastmittel; Kovalente organische Gerüste; Materialwissenschaften; - -Stapelung EN Fluoreszenz Kontrastmittel Kovalente organische Gerüste Materialwissenschaften - -Stapelung 10283 10283 1 06/08/20 20200615 NES 200615 B Ein kovalentes organisches Gerüst b (COF) aus Benzothiadiazolen mit effizienter Zwei-Photonen-induzierter Emission wurde von X. Z. Zhang und Mitarbeitern synthetisiert, wie in ihrem Forschungsartikel auf S. 10173 beschrieben wird. Die einzigartige Struktur des COF schwächt - -Stapelwechselwirkungen zwischen den Schichten ab und vermeidet eine aggregationsinduzierte Emissionslöschung. [Extracted from the article]