Rare-Earth Metal Complexes Supported by A Tridentate Amidinate Ligand: Synthesis, Characterization, and Catalytic Comparison in Isoprene Polymerization

To systematically investigate the dependence of the initiating group and metal size on polymerization performance, a family of rare-earth metal bis(alkyl)/bis(benzyl)/bis(amide) complexes supported by a monoanionic tridentate amidinate ligand [(2,6-iPr2C6H3)NC(Ph)N(C6H4-2-OMe]− (HL) were synthesized and well-characterized. Treatment of rare-earth metal tris(alkyl)/tris(benzyl)/tris(amide) complexes Y(CH2C6H4NMe2-o)3 or Y(CH2SiMe3)3(THF)2 or Ln[N(SiHMe2)2]3(THF)x (Ln = Sc, x = 1; Ln = Y, La, Sm, Lu, x = 2) with 1 equiv of HL gave the corresponding mono(amidinate) rare-earth metal bis(alkyl)/bis(benzyl)/bis(amide) complexes [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Y(CH2C6H4NMe2-o)2 (1), [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Y(CH2SiMe3)2(THF) (2), and [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Ln[N(SiHMe2)2]2(THF)n (Ln = Y, n = 1 (3); Ln = La, n = 1 (4); Ln = Sc, n = 0 (5); Ln = Lu, n = 0 (6); Ln = Sm, n = 0 (7)) in good isolated yields. These complexes were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction. In the presence of excess AlMe3 and on treatment with 1 equiv of [Ph3C][B(C6F5)4], these complexes could serve as precatalysts for cationic polymerization of isoprene, in which the dependence of the polymerization activity and regioselectivity on the initiating group and metal size was observed

Synthesis and Reactivity of N‑Heterocyclic Carbene Coordinated Formal Germanimidoyl-Phosphinidenes

Treatment of N-heterocyclic carbene (NHC) ligated germylidenylphosphinidene MsFluidtBu-GeP(NHCiPr) (where MsFluidtBu is a bulky hydrindacene substituent, and NHCiPr is 1,3-diisopropyl-4,5-dimethyl-imidazolin-2-ylidene) with mesityl azide and 4-tertbutylphenyl azide afforded NHC coordinated formal germanimidoyl-phosphinidenes, which represent the first compounds bearing both GeN double bond and phosphinidene functionalities. Studies of the chemical properties revealed that the reactions preferred to occur at the GeN double bond, which underwent [2 + 2] cycloadditions with CO2 and ethyl isocyanate, and coordinated with coinage metals through the nitrogen atom

Additional file 1 of Predictive value of delta radiomics in xerostomia after chemoradiotherapy in patients with stage III-IV nasopharyngeal carcinoma

Supplementary Material

High Energy Storage Density of Sandwich-Structured Na_0.5Bi_0.5TiO₃/PVDF Nanocomposites Enhanced by Optimizing the Dimensions of Fillers

The dielectric behavior and mechanisms of improved energy storage density of sandwich-structured different dimensions of Na0.5Bi0.5TiO3 /PVDF composites were studied. Compared with NBT-NPs/PVDF, optimized NBT-NFs/PVDF has a greater dielectric polarization strength, so the dielectric constant of NBT-NFs/PVDF is greater than that of composite materials filled with NBT-NPs with the same volume content. With the benefit from the addition of optimized high-aspect-ratio one-dimension NBT fiber as filler and the sandwich configuration for the composites, the experimental results prove that sandwich-structured NBT-NFs/PVDF can achieve a large energy storage density of 11.7 J/cm3 at a relatively lower electric field of 350 kV/mm for the composites with 1% volume fraction of NBT-NFs in the outer layers. The stronger polarization of composites filled by NBT-NFs is proved via electric modulus and the crystallinity of the composite films. Last but not least, the study found that composite materials also have excellent stable performance and good bending cycle stability. In summary, the composite materials obtained in this study can be used in electronic components for flexible energy storage in the future

Selective Capture and Manipulation of DNA through Double Charged Nanopores

In the past few decades, nanometer-scale pores have been employed as powerful tools for sensing biological molecules. Owing to its unique structure and properties, solid-state nanopores provide interesting opportunities for the development of DNA sequencing technology. Controlling DNA translocation in nanopores is an important means of improving the accuracy of sequencing. Here we present a proof of principle study of accelerating DNA captured across targeted graphene nanopores using surface charge density and find the intrinsic mechanism of the combination of electroosmotic flow induced by charges of nanopore and electrostatic attraction/repulsion between the nanopore and ssDNA. The theoretical study performed here provides a new means for controlling DNA transport dynamics and makes better and cheaper application of graphene in molecular sequencing

Immobilization of Oxygen Atoms in the Pores of Microporous Metal–Organic Frameworks for C₂H₂ Separation and Purification

The development of porous metal–organic framework (MOF) solids displaying efficient separation and purification of acetylene is of cardinal significance but challenging in the chemical industry. Among the reported MOFs for such a purpose, there usually exists an issue associated with trade-off between the uptake capacity and adsorption selectivity. In this work, we employed an N-oxide-functionalized dicarboxylate ligand to successfully construct under suitable solvothermal conditions a dicopper paddlewheel-based MOF featuring two different types of nanocages and rich open oxygen atoms on the channel surface. These structural features endow the material with the promising potential for C2H2 recovery from CO2 and CH4 at ambient conditions with impressive adsorption selectivity of C2H2 over CO2 and CH4 as well as considerable C2H2 capture capacity, which have been validated by isotherm measurements, ideal adsorbed solution theory calculations, and breakthrough experiments. Furthermore, molecular modeling studies revealed the vital role that the oxygen atoms coming from both N-oxide moieties and carboxylate groups play in selectively recognizing C2H2 over CO2 and CH4

Selective Capture and Manipulation of DNA through Double Charged Nanopores

In the past few decades, nanometer-scale pores have been employed as powerful tools for sensing biological molecules. Owing to its unique structure and properties, solid-state nanopores provide interesting opportunities for the development of DNA sequencing technology. Controlling DNA translocation in nanopores is an important means of improving the accuracy of sequencing. Here we present a proof of principle study of accelerating DNA captured across targeted graphene nanopores using surface charge density and find the intrinsic mechanism of the combination of electroosmotic flow induced by charges of nanopore and electrostatic attraction/repulsion between the nanopore and ssDNA. The theoretical study performed here provides a new means for controlling DNA transport dynamics and makes better and cheaper application of graphene in molecular sequencing

Immobilization of Oxygen Atoms in the Pores of Microporous Metal–Organic Frameworks for C₂H₂ Separation and Purification

The development of porous metal–organic framework (MOF) solids displaying efficient separation and purification of acetylene is of cardinal significance but challenging in the chemical industry. Among the reported MOFs for such a purpose, there usually exists an issue associated with trade-off between the uptake capacity and adsorption selectivity. In this work, we employed an N-oxide-functionalized dicarboxylate ligand to successfully construct under suitable solvothermal conditions a dicopper paddlewheel-based MOF featuring two different types of nanocages and rich open oxygen atoms on the channel surface. These structural features endow the material with the promising potential for C2H2 recovery from CO2 and CH4 at ambient conditions with impressive adsorption selectivity of C2H2 over CO2 and CH4 as well as considerable C2H2 capture capacity, which have been validated by isotherm measurements, ideal adsorbed solution theory calculations, and breakthrough experiments. Furthermore, molecular modeling studies revealed the vital role that the oxygen atoms coming from both N-oxide moieties and carboxylate groups play in selectively recognizing C2H2 over CO2 and CH4

DataSheet_1_Prediction of Response to Induction Chemotherapy Plus Concurrent Chemoradiotherapy for Nasopharyngeal Carcinoma Based on MRI Radiomics and Delta Radiomics: A Two-Center Retrospective Study.docx

ObjectiveWe aimed to establish an MRI radiomics model and a Delta radiomics model to predict tumor retraction after induction chemotherapy (IC) combined with concurrent chemoradiotherapy (CCRT) for primary nasopharyngeal carcinoma (NPC) in non-endemic areas and to validate its efficacy.MethodsA total of 272 patients (155 in the training set, 66 in the internal validation set, and 51 in the external validation set) with biopsy pathologically confirmed primary NPC who were screened for pretreatment MRI were retrospectively collected. The NPC tumor was delineated as a region of interest in the two sequenced images of MRI before treatment and after IC, followed by radiomics feature extraction. With the use of maximum relevance minimum redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithms, logistic regression was performed to establish pretreatment MRI radiomics and pre- and post-IC Delta radiomics models. The optimal Youden’s index was taken; the receiver operating characteristic (ROC) curve, calibration curve, and decision curve were drawn to evaluate the predictive efficacy of different models.ResultsSeven optimal feature subsets were selected from the pretreatment MRI radiomics model, and twelve optimal subsets were selected from the Delta radiomics model. The area under the ROC curve, accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the MRI radiomics model were 0.865, 0.827, 0.837, 0.813, 0.776, and 0.865, respectively; the corresponding indicators of the Delta radiomics model were 0.941, 0.883, 0.793, 0.968, 0.833, and 0.958, respectively.ConclusionThe pretreatment MRI radiomics model and pre- and post-IC Delta radiomics models could predict the IC-CCRT response of NPC in non-epidemic areas.</p

Gate-Tunable Quantum Acoustoelectric Transport in Graphene

Transport probes the motion of quasi-particles in response to external excitations. Apart from the well-known electric and thermoelectric transport, acoustoelectric transport induced by traveling acoustic waves has rarely been explored. Here, by adopting hybrid nanodevices integrated with piezoelectric substrates, we establish a simple design of acoustoelectric transport with gate tunability. We fabricate dual-gated acoustoelectric devices based on hBN-encapsulated graphene on LiNbO3. Longitudinal and transverse acoustoelectric voltages are generated by launching a pulsed surface acoustic wave. The gate dependence of zero-field longitudinal acoustoelectric signal presents strikingly similar profiles to that of Hall resistivity, providing a valid approach for extracting carrier density without magnetic field. In magnetic fields, acoustoelectric quantum oscillations appear due to Landau quantization, which are more robust and pronounced than Shubnikov-de Haas oscillations. Our work demonstrates a feasible acoustoelectric setup with gate tunability, which can be extended to the broad scope of various van der Waals materials