Synthesis of Cyclohexene Carbonate Catalyzed by Polymer-Supported Catalysts

<div><p></p><p>A series of polystyrene-divinylbenzene cross-linked resin (PS)–supported zinc chloride catalysts were prepared in this study. They can efficiently catalyze the solventless cycloaddition of cyclohexene oxide with carbon dioxide in the presence of tetrabutylammonium bromide (TBAB) as cocatalyst under relatively mild reaction conditions. The catalyst is composed of carrier, connecting arm, ligand, and active ingredient. The connecting arms of different lengths can significantly affect the catalytic activity. Among these catalysts, the one using diethylene glycol as connecting arm and 2-aminopyridine as ligand, named PS-DEG-2ap-ZnCl₂, showed the optimal catalytic performance. The yield of cyclohexene carbonate was 95.18% calculated by gas chromatographic analysis under the optimal conditions (393 K, 5 MPa, 6 h). Moreover, the catalyst showed good stability and reusability. From the viewpoint of industrial application, the catalyst is attractive because of its excellent catalytic efficiency on the synthesis of cyclohexene carbonate.</p></div

Image_3_The top 100 most cited articles in helical tomotherapy: a scoping review.jpeg

ObjectiveThe purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.MethodsThe Web of Science Core Collection and the search strategy of “Title (TI)=(tomotherapy)” were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting “citations: highest first”. From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.ResultsThe top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).ConclusionThis scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.</p

Image_2_The top 100 most cited articles in helical tomotherapy: a scoping review.jpeg

ObjectiveThe purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.MethodsThe Web of Science Core Collection and the search strategy of “Title (TI)=(tomotherapy)” were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting “citations: highest first”. From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.ResultsThe top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).ConclusionThis scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.</p

Amorphous Conjugated Carbazole Trimers for Photorefractive Materials

New conjugated carbazole trimers for photorefractive materials have been synthesized by Pd-catalytic coupling reaction. These trimers were demonstrated to be amorphous by both differential scanning calorimeter and X-ray diffraction. In these carbazole trimers, three carbazole rings are π-conjugated through ethynyl group and act as a charge transporting agent. Peripheral carbazoles substituted with acceptor groups can be served as an electrooptic chromophore. The photoconductivity, electrooptic effect, and photorefractive properties of the conjugated carbazole trimer substituted with dicyanovinyl group doped with 2,4,7-trinitro-9-fluorenone as a sensitizer are reported

Table_1_The top 100 most cited articles in helical tomotherapy: a scoping review.docx

ObjectiveThe purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.MethodsThe Web of Science Core Collection and the search strategy of “Title (TI)=(tomotherapy)” were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting “citations: highest first”. From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.ResultsThe top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).ConclusionThis scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.</p

Table_2_The top 100 most cited articles in helical tomotherapy: a scoping review.docx

ObjectiveThe purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.MethodsThe Web of Science Core Collection and the search strategy of “Title (TI)=(tomotherapy)” were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting “citations: highest first”. From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.ResultsThe top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).ConclusionThis scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.</p

Image_1_The top 100 most cited articles in helical tomotherapy: a scoping review.jpeg

ObjectiveThe purpose of this scoping review was to explore the top 100 most cited articles in helical tomotherapy (HT) through bibliometric analysis and visualization tools, help researchers comprehensively understand the research hotspots of HT, and provide clear and intuitive network visualization.MethodsThe Web of Science Core Collection and the search strategy of “Title (TI)=(tomotherapy)” were used to search for articles related to HT as of 27 May 2023. The top 100 most cited articles were obtained by sorting “citations: highest first”. From these top 100 most cited articles, the following information was extracted: journals, years and months, countries, authors, types of tumor treated, and topics. The VOSviewer software was introduced for visualizing all the articles related to HT.ResultsThe top 100 most cited articles in HT were published between 1999 and 2019. The citation counts of these articles ranges from 326 to 45, with a total of 8,422 citations at the time of searching. The index of citations per year (CPY) ranges from 22.32 to 2.45. These articles originated from 17 countries, with most publications from the United States (n=50), followed by Canada (n=12), Italy (n=10), Germany (n=7) and Belgium (n=5). The International Journal of Radiation Oncology, Biology, Physics published the highest number of articles (n=31), followed by Radiotherapy and Oncology (n=20), Medical Physics (n=13) and Strahlentherapie und Onkologie (n=12). In terms of specific tumor types, head and neck cancer (n=15) is the most common disease, followed by cancers with complex target structures (n=14), breast cancer (n=12), prostate cancer (n=10) and lung cancer (n=8). The most common research topics also include dosimetric comparison (n = 44), quality assurance (n = 12) and Megavoltage CT (n = 8).ConclusionThis scoping review provides a comprehensive list of the 100 most cited articles in HT. This analysis offers valuable insights into the current research directions of HT that can be utilized by researchers, clinicians, and policy-makers.</p

Computational Screening of Single Non-Noble Transition-Metal Atoms Confined Inside Boron Nitride Nanotubes for CO Oxidation

Based on density functional theory calculations, the stability and catalytic activity of a series of single non-noble transition-metal (TM) atoms confined on the interior surface of boron nitride nanotubes (BNNTs) with nitrogen vacancy for CO oxidation have been systematically studied. By searching for the reaction pathways of CO oxidation in the Eley–Rideal (ER) mechanism catalyzed by single TM atoms (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn) confined inside BNNT­(6,6), we found that Cu–BNNT­(6,6) and Mn–BNNT­(6,6) are good candidates as highly efficient catalysts, with the energy barriers of the rate-determining step for CO oxidation being 0.24 and 0.37 eV, respectively. Compared with ER reactions, CO oxidation proceeds via the Langmuir–Hinshelwood mechanism with relatively larger energy barriers. We confirmed that the interior surface of BNNT­(6,6) provides a better confinement environment than the exterior surface for developing single-atom catalysts. With the appropriate energy barriers, Cu–BNNT­(6,6) and Mn–BNNT­(6,6) show the satisfactory catalytic performance for CO oxidation

Table_1_OsNAR2.1 induced endogenous nitrogen concentration variation affects transcriptional expression of miRNAs in rice.xlsx

The studies of rice nitrogen concentration on the expression of miRNA so far are mostly limited to the exogenous nitrogen, leaving the effect of endogenous nitrogen largely unexplored. OsNAR2.1 is a high-affinity nitrate transporter partner protein which plays a central role in nitrate absorption and translocation in rice. The expression of OsNAR2.1 could influence the concentration of the endogenous nitrogen in rice. We showed that the expression and production of miRNA in rice can be influenced by manipulating the endogenous nitrogen concentration via OsNAR2.1 transgenic lines. The small RNA content, particularly 24 nucleotides small RNA, expressed differently in two transgenic rice lines (nitrogen efficient line with overexpression of OsNAR2.1 (Ov199), nitrogen-inefficient line with knockdown OsNAR2.1 by RNAi (RNAi)) compared to the wild-type (NP). Comparative hierarchical clustering expression pattern analysis revealed that the expression profiles of mature miRNA in both transgenic lines were different from NP. Several previously unidentified miRNAs were identified to be differentially expressed under different nitrogen concentrations, namely miR1874, miR5150, chr3-36147, chr4-27017 and chr5-21745. In conclusion, our findings suggest that the level of endogenous nitrogen concentration variation by overexpression or knockdown OsNAR2.1 could mediate the expression pattern and intensity of miRNA in rice, which is of high potential to be used in molecular breeding to improve the rice responses towards nitrogen utilization.</p

Impact of Alkyl-Functionalized BTC on Properties of Copper-Based Metal–Organic Frameworks

Highly porous metal–organic frameworks (MOFs) [Cu₃(MBTC)₂(H₂O)₃]_<i>n</i> (where MBTC is methyl-1,3,5-benzenetricarboxylate) and [Cu₃(EBTC)₂(H₂O)₃]_<i>n</i> (where EBTC is ethyl-1,3,5-benzenetricarboxylate) have been solvothermally synthesized. The MOFs are isostructural to each other but do not form the same framework as HKUST-1 (CuBTC) due to the steric impact of the alkyl-functionalized ligands. The new MOFs are formed by two different [Cu₂(O₂CR)₄] units (where R is an aromatic ring), which create the three-dimensional framework with open-metal sites and high surface areas. Compared with HKUST-1, these MOFs adsorb comparable amounts of carbon dioxide and methane at pressures up to 5 bar. However, water adsorption is significantly lower compared to HKUST-1 due to the hydrophobic functional groups. This work indicates that the strong adsorption preference of water on open-metal sites can be limited with the proper choice of the hydrophobic functional groups, without losing the strong interaction with other gases