Search

The keto‐switched photocatalysis of covalent organic frameworks (COFs) for efficient H2 evolution was reported for the first time by engineering, at a molecular level, the local structure and component of the skeletal building blocks. A series of imine‐linked BT‐COFs were synthesized by the Schiff‐base reaction of 1, 3, 5‐benzenetrialdehyde with diamines to demonstrate the structural reconstruction of enol to keto configurations by alkaline catalysis. The keto groups of the skeletal building blocks served as active injectors, where hot π‐electrons were provided to Pt nanoparticles (NPs) across a polyvinylpyrrolidone (PVP) insulting layer. The characterization results, together with density functional theory calculations, indicated clearly that the formation of keto‐injectors not only made the conduction band level more negative, but also led to an inhomogeneous charge distribution in the donor‐acceptor molecular building blocks to form a strong intramolecular built‐in electric field. As a result, visible‐light photocatalysis of TP‐COFs‐1 with one keto group in the skeletal building blocks was successfully enabled and achieved an impressive H2 evolution rate as high as 0.96 mmol g−1 h−1. Also, the photocatalytic H2 evolution rates of the reconstructed BT‐COFs‐2 and ‐3 with two and three keto‐injectors were significantly enhanced by alkaline post‐treatment. [ABSTRACT FROM AUTHOR]

Crystalline covalent organic frameworks (COFs) are porous polymeric semiconductors with network topologies, which are built from the integration of selected organic blocks with covalent bond linkages. They have shown great promise for artificial photosynthesis, owing to broad light harvesting, high crystallinity, and high carrier mobility. This Minireview introduces state‐of‐the‐art COF photocatalysts based on different linkages and discusses the origin of photocatalytic activities for hydrogen evolution. Three typical COF photocatalysts, with linkages including imine (−C=N−), β‐ketoenamine (O=C−C=C−NH−), and vinylene (−C=C−), are discussed with a particular focus on the advancements in synthetic methodologies and structural design, as well as photoelectronic properties that are relevant to photocatalytic performance. The Minireview is expected to elucidate their structure–property relationships and the way to design photoactive COFs with enhanced performances. [ABSTRACT FROM AUTHOR]

The Yinggen‐Ejinaqi Basin (YEB) is located in the central‐southern part of the Central Asian Orogenic Belt (CAOB). Tectonically, the basin is situated at the intersection between the eastern and western CAOB, where Late Palaeozoic strata were well exposed. Hence, it offers a great opportunity to study the deep strata of the eastern CAOB. In this paper, based on extensive studies of Upper Palaeozoic field outcrops and reanalysis of associated geochemical and geochronological data in previous research, the local stratigraphic correlation is established, and the tectonic evolution, sedimentary filling, sedimentary characteristics, and petroleum system of the YEB are discussed. It is revealed that: (a) The filling characteristics of the Upper Palaeozoic strata in YEB are closely related to the closure of the Paleo‐Asian Ocean (PAO). YEB underwent subduction‐related compression during the initial extensional phase of the fore‐arc basin from the Viséan to the Serpukhovian (late Early Carboniferous). During the Bashkirian–Sakmarian interval (Late Carboniferous to Early Permian), it was in subduction‐related fore‐arc and postarc rifting phases. During the Artinskian–Capitanian (Early‐Middle Permian) times, it was in an intracontinental rifting‐depression phase. During the Wuchapingian (Late Permian), it was in an intracontinental compressional phase. Tectonostratigraphy, tectonic evolution, and hydrocarbon potential assessments of the study area show that the Zhusileng Hangwula‐Tost Ul tectonic zone (ZHTUTZ) and southwestern part of Querrshan‐Atasbogd tectonic zone (QATZ) are identified as the main prospective areas for the exploration in the YEB. (b) According to the tectonostratigraphic analysis, tectonic evolution and hydrocarbon system of Carboniferous–Permian in the YEB, the YEB has similar attributes to the basin province in western CAOB (e.g., Santanghu and Junggar basins) and eastern CAOB (Erlian, Songliao Basin). To explore commercial oil and gas in the deeper strata (Carboniferous–Permian) of the eastern CAOB basins, further tectonostratigraphic analyses and comprehensive assessment on hydrocarbon potentials are necessitated in the near future. [ABSTRACT FROM AUTHOR]

Background: Patient-derived xenograft (PDX) models increasingly are used in translational research. However, the engraftment rates of patient tumor samples in immunodeficient mice to PDX models vary greatly.Methods: Tumor tissue samples from 308 patients with non-small cell lung cancer were implanted in immunodeficient mice. The patients were followed for 1.5 to approximately 6 years. The authors performed histological analysis of PDXs and some residual tumor tissues in mice with failed PDX growth at 1 year after implantation. Quantitative polymerase chain reaction and enzyme-linked immunoadsorbent assay were performed to measure the levels of Epstein-Barr virus genes and human immunoglobulin G in PDX samples. Patient characteristics were compared for PDX growth and overall survival as outcomes using Cox regression analyses. Disease staging was based on the 7th TNM staging system.Results: The overall engraftment rate for PDXs from patients with non-small cell lung cancer was 34%. Squamous cell carcinomas had a higher engraftment rate (53%) compared with adenocarcinomas. Tumor samples from patients with stage II and stage III disease and from larger tumors were found to have relatively high engraftment rates. Patients whose tumors successfully engrafted had worse overall survival, particularly those individuals with adenocarcinoma, stage III or stage IV disease, and moderately differentiated tumors. Lymphoma formation was one of the factors associated with engraftment failure. Human CD8-positive and CD20-positive cells were detected in residual samples of tumor tissue that failed to generate a PDX at 1 year after implantation. Human immunoglobulin G was detected in the plasma of mice that did not have PDX growth at 14 months after implantation.Conclusions: The results of the current study indicate that the characteristics of cancer cells and the tumor immune microenvironment in primary tumors both can affect engraftment of a primary tumor sample. [ABSTRACT FROM AUTHOR]

Purpose To investigate the quality of written instructions for dental prostheses in China, including metal-ceramic fixed restorations and removable partial dentures (RPDs). Materials and Methods A total of 1600 prepiloted questionnaires were distributed to five major commercial dental laboratories in different regions in China. The opinions of dental technicians on the written instructions provided by dentists were investigated. In addition, this study also revealed the technicians' responses to poorly written instructions. Results Seven percent of the written instructions clarified the disinfection status of the impressions or casts, while 32% of the instructions provided general patient information (e.g., gender and age). In cases of metal-ceramic fixed restorations, percentages of written instructions specifying shade, ceramic veneering area, and margin design were 72%, 20%, and 9%, respectively. In fixed partial denture cases, 60% of written instructions provided the number of pontics, while 22% specified the pontic design. In the case of RPDs, 90% of instructions showed the type and position of clasps, 88% provided connector design, while 68% mentioned information regarding the artificial teeth. Dental technicians claimed that 78% of the written instructions involved were inadequately prescribed to some extent, but only about one-third of them would contact dentists for clarification. Conclusions Written instructions are not well prescribed in many cases. This situation may jeopardize the quality of prosthodontic treatment. It is necessary to shape responsible policy and mandatory professional guidelines for prosthodontic treatment procedures including dental laboratory services. [ABSTRACT FROM AUTHOR]

In the title polymeric heterometallic compound, {[Cu(3)Gd(C(6)H(4)NO(2))(3)Cl(3)(H(2)O)(2)]·0.5H(2)O}(n), comprising copper(I) and gadolinium(III) cations bridged by nicotinate (nic) ligands and chloride anions, the Gd(III) centers display a bicapped trigonal prismatic geometry, defined by six carboxylate O atoms and two water molecules. For copper(I), one Cu center is three-coordinated by three chloride ions and displays a trigonal-planar geometry; the other two Cu centers are four-coordinated and display a very distorted tetrahedral geometry. The chloride anions act in μ(2)- and μ(3)-bridging modes, linking the Cu(I) ions into an infinite chain. The nic ligand exhibits a tridentate coordination mode, with the carboxylate O atoms linking to two Gd(III) ions and the N atom linking to one Cu(I) ion. Thus, a novel three-dimensional heterometallic coordination polymer is constructed from Gd-carboxylate subunits and Cu-Cl chains. In addition, intra- and intermolecular O-H···O and O-H···Cl hydrogen bonds are also observed within the three-dimensional structure. Topologically, the framework represents an unusual 3,6-connected (4.8(2))(3)(4(10).6(5)) net., (© 2011 International Union of Crystallography)