Doxorubicin-Loaded Photosensitizer-Core pH-Responsive Copolymer Nanocarriers for Combining Photodynamic Therapy and Chemotherapy

Photodynamic therapy (PDT) is an emerging method for the treatment of cancer. Combination of PDT and chemotherapy is a hot topic though the two therapies could not simultaneously exert their perfect effect in vivo. Here we report a doxorubicin-loaded photosensitizer-core pH-responsive copolymer nanocarrier with high tumor targeting and anticancer effects due to integration of PDT with chemotherapy. The pH-responsive photosensitizer-core four-armed star-shaped copolymer, [methoxy-poly­(ethylene glycol)-poly­(2-(N,N-diethylamino)­ethyl methacrylate)-poly­(ε-caprolactone)]₄-zinc β-tetra-(4-carboxyl benzyloxyl)­phthalocyanine (PDCZP), was prepared, which was a molecular spherical nanocarrier in aqueous media. The carriers changed from small at high pH to large at low pH (51, 105, and 342 nm at pH 7.4, 6.5, and 5.0, respectively) and the zeta potential gradually increased (7.15, 16.2, and 26.1 mV at the above pH, respectively). PDCZP had a longer emission wavelength (max. 677 nm) than the parent photosensitizer, favoring light penetration through biological tissues. The singlet oxygen (¹O₂) quantum yield of PDCZP was 0.41. Doxorubicin (DOX) showed rapid release from PDCZP in the acidic media. More importantly, the drug-loaded nanocarriers showed the better in vitro and in vivo anticancer effects under lighting on MCF-7, SW480 cells and HepG2 cells and the murine hepatocellular carcinoma H₂₂ models than the other groups. PDCZP showed a high tumor targeting effect based on the enhanced permeation and retention effect and its small size. The photosensitizer-core nanocarrier is a promising photodynamic nanocarrier for integrating other therapies

Theoretical Investigation of Water Gas Shift Reaction Catalyzed by Iron Group Carbonyl Complexes M(CO)₅ (M = Fe, Ru, Os)

We have investigated the mechanism of M­(CO)₅ (M = Fe, Ru, Os) catalyzed water gas shift reaction (WGSR) by using density functional theory and ab initio calculations. Our calculation results indicate that the whole reaction cycle consists of six steps: <b>1</b> → <b>2</b> → <b>3</b> → <b>4</b> → <b>5</b> → <b>6</b> → <b>2</b>. In this stepwise mechanism the metals Fe, Ru, and Os behave generally in a similar way. However, crucial differences appear in steps <b>3</b> → <b>4</b> → <b>5</b> which involve dihydride M­(H)₂(CO)₃COOH^– (<b>4′</b>) and/or dihydrogen complex MH₂(CO)₃COOH^– (<b>4</b>). The stability of the dihydrogen complexes becomes weaker down the iron group. The dihydrogen complex <b>4_Fe</b> is only 11.1 kJ/mol less stable than its dihydride <b>4′_Fe</b> at the B3LYP/II­(f)++//B3LYP/II­(f) level. Due to very low energy barrier it is very easy to realize the transform from <b>4_Fe</b> to <b>4′_Fe</b> and vice versa, and thus for Fe there is no substantial difference to differentiate <b>4</b> and <b>4′</b> for the reaction cycle. The most possible key intermediate <b>4′_Ru</b> is 38.2 kJ/mol more stable than <b>4_Ru</b>. However, the barrier for the conversion <b>3_Ru</b> → <b>4′_Ru</b> is 23.8 kJ/mol higher than that for <b>3_Ru</b> → <b>4_Ru</b>. Additionally, <b>4′_Ru</b> has to go through <b>4_Ru</b> to complete dehydrogenation <b>4′_Ru</b> → <b>5_Ru</b>. The concerted mechanism <b>4′_Ru</b> → <b>6_Ru</b>, in which the CO group attacks ruthenium while H₂ dissociates, can be excluded. In contrast to Fe and Ru, the dihydrogen complex of Os is too unstable to exist at the level of theory. Moreover, we predict Fe and Ru species are more favorable than Os species for the WGSR, because the energy barriers for the <b>4</b> → <b>5</b> processes of Fe and Ru are only 38.9 and 16.2 kJ/mol, respectively, whereas 140.5 kJ/mol is calculated for the conversion <b>4′</b> → <b>5</b> of Os, which is significantly higher. In general, the calculations are in good agreement with available experimental data. We hope that our work will be beneficial to the development and design of the WGSR catalyst with high performance

Covalent modification of temperature-sensitive breathable polyurethane with carbon nanotubes

<p>Intelligent breathable polyurethane (PU) that is easily allowable for vapor transmission at critical temperature would have significant implication for numerous applications; however, fabrication of such materials has proven to be tremendously challenging. Herein, we reported novel breathable polyurethane material covalently modified with carbon nanotubes (CNTs). When an optimal amount of CNTs (0.5 wt%) was added, the resultant PU film presented high waterproofness with hydrostatic pressure up to 10.9 kPa, as well as enhanced mechanical properties with a tensile strength of 22.2 kPa and elongation at break of 990%. This smart PU film has a significant increase in water vapor transmission rate between 18°C (1400 g/(m²·d)) and 38°C (3440 g/(m²·d)). The type of intelligent polyurethane material is a promising candidate for applications in areas such as protective clothing, separator media, and wearable electronics.</p

Quantifying the impact of scholarly papers based on higher-order weighted citations

<div><p>Quantifying the impact of a scholarly paper is of great significance, yet the effect of geographical distance of cited papers has not been explored. In this paper, we examine 30,596 papers published in Physical Review C, and identify the relationship between citations and geographical distances between author affiliations. Subsequently, a relative citation weight is applied to assess the impact of a scholarly paper. A higher-order weighted quantum PageRank algorithm is also developed to address the behavior of multiple step citation flow. Capturing the citation dynamics with higher-order dependencies reveals the actual impact of papers, including necessary self-citations that are sometimes excluded in prior studies. Quantum PageRank is utilized in this paper to help differentiating nodes whose PageRank values are identical.</p></div

Visualizing citations between institutions.

<p>Visualizing citations between institutions.</p

Comparing self-citation weights in two different citation networks.

<p>Comparing self-citation weights in two different citation networks.</p

Synthesis, Characterization, and Photophysical and Electroluminescent Properties of Blue-Emitting Cationic Iridium(III) Complexes Bearing Nonconjugated Ligands

The development of pure-blue-to-deep-blue-emitting ionic phosphors is an ultimate challenge for full-color displays and white-light sources. Herein we report two series of short-wavelength light-emitting cationic iridium­(III) complexes with nonconjugated ancillary and cyclometalating ligands, respectively. In the first series, nonconjugated 1-[(diphenylphosphino)­methyl]-3-methylimidazolin-2-ylidene-C,C₂′ (dppmmi) is used as the ancillary ligand and 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)­pyridine (dfppy), and 1-(2,4-difluorophenyl)-1<i>H</i>-pyrazole (dfppz) are used as cyclometalating ligands. In the second one, nonconjugated 2,4-difluorobenzyl-<i>N</i>-pyrazole (dfbpz) is used as the cyclometalating ligand and 3-methyl-1-(2-pyridyl)­benzimidazolin-2-ylidene-C,C²′ (pymbi) as the ancillary ligand. The synthesis and photophysical and electrochemical properties, together with the X-ray crystal structures of these complexes, have been investigated. At room temperature, blue-emitting complexes [Ir­(ppy)₂(dppmmi)]­PF₆ (<b>1</b>) and [Ir­(dfppy)₂(dppmmi)]­PF₆ (<b>2</b>; PF₆^– is hexafluorophosphate) show much larger photoluminescence quantum yields of 24% and 46%, respectively. On the contrary, for complexes [Ir­(dfppz)₂(dppmmi)]­PF₆ (<b>3</b>) and [Ir­(dfbpz)₂(pymbi)]­PF₆ (<b>4</b>), deep-blue luminescence is only observed at low temperature (77 K). Density functional theory calculations are used to rationalize the differences in the photophysical behavior observed upon changes of the ligands. It is shown that the electronic transition dipoles of cationic iridium complexes <b>1</b> and <b>2</b> are mainly confined to cyclometalated ligands (³MLCT and LC ³π–π*) and those of complex <b>3</b> are confined to all of the ligands (³MLCT, LC ³π–π*, and ³LLCT) because of the high LUMO energy level of dfppz. The emission of <b>4</b> mainly originates from the central iridium­(III) ion and cyclometalated ligand to ancillary ligand charge transfer (³MLCT and ³LLCT), in contrast to commonly designed cationic complexes using carbene-type ancillary ligands, where emission originates from the cyclometalated main ligands. Solution-processed organic light-emitting diodes based on complexes <b>1</b> and <b>2</b> gave blue-green (498 nm) and blue (478 nm) electroluminescence with maximum current efficiencies of 3.8 and 3.4 cd A^–1, respectively. The results indicate that introducing nonconjugated ligands into cationic iridium complexes is an effective means of achieving short-wavelength light-emitting phosphors

Characterizing the relationship of citations and geographical distance by grouping analysis.

<p>Characterizing the relationship of citations and geographical distance by grouping analysis.</p

Presentation_1_Genome-wide identification of cystathionine beta synthase genes in wheat and its relationship with anther male sterility under heat stress.pptx

Cystathionine beta synthase (CBS) domains containing proteins (CDCPs) plays an important role in plant development through regulation of the thioredoxin system, as well as its ability to respond to biotic and abiotic stress conditions. Despite this, no systematic study has examined the wheat CBS gene family and its relation to high temperature-induced male sterility. In this study, 66 CBS family members were identified in the wheat genome, and their gene or protein sequences were used for subsequent analysis. The TaCBS gene family was found to be unevenly distributed on 21 chromosomes, and they were classified into four subgroups according to their gene structure and phylogeny. The results of collinearity analysis showed that there were 25 shared orthologous genes between wheat, rice and Brachypodium distachyon, and one shared orthologous gene between wheat, millet and barley. The cis-regulatory elements of the TaCBS were related to JA, IAA, MYB, etc. GO and KEGG pathway analysis identified these TaCBS genes to be associated with pollination, reproduction, and signaling and cellular processes, respectively. A heatmap of wheat plants based on transcriptome data showed that TaCBS genes were expressed to a higher extent in spikelets relative to other tissues. In addition, 29 putative tae-miRNAs were identified, targeting 41 TaCBS genes. Moreover, qRT-PCR validation of six TaCBS genes indicated their critical role in anther development, as five of them were expressed at lower levels in heat-stressed male sterile anthers than in Normal anthers. Together with anther phenotypes, paraffin sections, starch potassium iodide staining, and qRT-PCR data, we hypothesized that the TaCBS gene has a very important connection with the heat-stressed sterility process in wheat, and these data provide a basis for further insight into their relationship.</p

Visualizing the geographical distribution of institutions.

<p>Visualizing the geographical distribution of institutions.</p