다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Metal Oxides and Oxysalts as Anode Materials for Li Ion Batteries

At present, the actual mechanism of the photoluminescence (PL) of fluorescent carbon dots (CDs) is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved: graphene quantum dots (GQDs), carbon nanodots (CNDs), and polymer dots (PDs). Four reasonable PL mechanisms have been confirmed: the quantum confinement effect or conjugated π-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink-enhanced emission (CEE) effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.

The photoluminescence mechanism in carbon dots (graphene quantum dots, carbon nanodots, and polymer dots): current state and future perspective

First principles calculations were performed to investigate the structural, elastic, and electronic properties of IrN2 for various space groups: cubic Fm-3m and Pa-3, hexagonal P3(2)21, tetragonal P4(2)/mnm, orthorhombic Pmmn, Pnnm, and Pnn2, and monoclinic P2(1)/c. Our calculation indicates that the P2(1)/c phase with arsenopyrite-type structure is energetically more stable than the other phases. It is semiconducting (the remaining phases are metallic) and contains diatomic N-N with the bond distance of 1.414 A. These characters are consistent with the experimental facts that IrN2 is in lower symmetry and nonmetallic. Our conclusion is also in agreement with the recent theoretical studies that the most stable phase of IrN2 is monoclinic P2(1)/c. The calculated bulk modulus of 373 GPa is also the highest among the considered space groups. It matches the recent theoretical values of 357 GPa within 4.3% and of 402 GPa within 7.8%, but smaller than the experimental value of 428 GPa by 14.7%. Chemical bonding and potential displacive phase transitions are discussed for IrN2. For IrN3, cubic skutterudite structure (Im-3) was assumed.

Crystal structures and elastic properties of superhard IrN2 and IrN3 from first principles

We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

A FRET-based carbon nanodot (CDot) drug delivery platform has been developed. These CDots offer excellent biocompatibility, stable fluorescence, and efficient FRET between CDots and the attached fluorescent drug molecules, such as doxorubicin, enabling enhanced drug delivery, convenient cell imaging, and real-time monitoring of drug release. Moreover, the FRET-based two-photon imaging and drug tracking in deep tissues are also demonstrated.

Carbon Nanodots Featuring Efficient FRET for Real-Time Monitoring of Drug Delivery and Two-Photon Imaging

We demonstrate for the first time the controlled Sn-doping in TiO2 nanowire (NW) arrays for photoelectrochemical (PEC) water splitting. Because of the low lattice mismatch between SnO2 and TiO2, Sn dopants are incorporated into TiO2 NWs by a one-pot hydrothermal synthesis with different ratios of SnCl4 and tetrabutyl titanate, and a high acidity of the reactant solution is critical to control the SnCl4 hydrolysis rate. The obtained Sn-doped TiO2 (Sn/TiO2) NWs are single crystalline with a rutile structure, and the incorporation of Sn in TiO2 NWs is well controlled at a low level, that is, 1–2% of Sn/Ti ratio, to avoid phase separation or interface scattering. PEC measurement on Sn/TiO2 NW photoanodes with different Sn doping ratios shows that the photocurrent increases first with increased Sn doping level to >2.0 mA/cm2 at 0 V vs Ag/AgCl under 100 mW/cm2 simulated sunlight illumination up to ∼100% enhancement compared to our best pristine TiO2 NW photoanodes and then decreases at higher Sn doping levels. ...

Controlled Sn-Doping in TiO2 Nanowire Photoanodes with Enhanced Photoelectrochemical Conversion

We have developed sensitive detection of glutathione using the IrO2–hemin–TiO2 nanowire arrays. Single-crystalline TiO2 nanowires are synthesized by a hydrothermal reaction, followed by surface functionalization of ∼3 nm thick hemin and ∼1–2 nm diameter IrO2 nanoparticles. The IrO2–hemin–TiO2 nanowire arrays offer much enhanced photocurrent with ∼100% increase compared to the pristine TiO2 nanowires and allow for label-free, real-time, sensitive photoelectrochemical detection of glutathione. The sensitivity achieved is ∼10 nM in buffer, comparable to or better than most of the existing glutathione detection methods. Furthermore, cell extracts containing glutathione are robustly detected, with ∼8000 cells/mL for HeLa cells and ∼5000 cells/mL for human embryonic kidney 293T cells. This nanowire PEC sensor assay exhibits excellent selectivity and stability, suggesting a potential detection platform for analyzing the glutathione level in biosamples.

Photoelectrochemical Detection of Glutathione by IrO2–Hemin–TiO2 Nanowire Arrays

Temperature is an essential factor that counts for living systems where complicated vital activities are usually temperature dependent. In vivo temperature mapping based on non-contact optical approach will be beneficial for revealing the physiological phenomena behind with minimized influence to the organism. Herein, a highly thermal-sensitive upconversion system based on triplet–triplet annihilation (TTA) mechanism is pioneered to indicate body temperature variation sensitively over the physiological temperature range. The temperature-insensitive NaYF4: Nd nanophosphors with NIR emission was incorporated into the temperature-responsive TTA-upconversion system to serve as an internal calibration unit. Consequently, a ratiometric thermometer capable of accurately monitoring the temperature changes in vivo was developed with high thermal sensitivity (~7.1% K−1) and resolution (~0.1 K). Though luminescence imaging is a promising approach for contactless thermometry in vivo, the low thermal sensitivity of existing thermometers limits its potential. Here, the authors develop a high-sensitivity ratiometric nanothermometer based on triplet-sensitized upconversion.

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Ratiometric nanothermometer in vivo based on triplet sensitized upconversion

We report a facile, two-step hydrothermal synthesis of a novel Co3O4/α-Fe2O3 branched nanowire heterostructure, which can serve as a good candidate for lithium-ion battery anodes with high Li+ storage capacity and stability. The single-crystalline, primary Co3O4 nanowire trunk arrays directly grown on Ti substrates allow for efficient electrical and ionic transport. The secondary α-Fe2O3 branches provide enhanced surface area and high theoretical Li+ storage capacity, and can also serve as volume spacers between neighboring Co3O4 NW arrays to maintain electrolyte penetration as well as reduce the aggregation during Li+ intercalation, thus leading to improved electrochemical energy storage performance.

Ming Xu

Papers

Carbon Nanodots Featuring Efficient FRET for Real-Time Monitoring of Drug Delivery and Two-Photon Imaging

Controlled Sn-Doping in TiO2 Nanowire Photoanodes with Enhanced Photoelectrochemical Conversion

Photoelectrochemical Detection of Glutathione by IrO2–Hemin–TiO2 Nanowire Arrays

Ratiometric nanothermometer in vivo based on triplet sensitized upconversion

Branched Co3O4/Fe2O3 nanowires as high capacity lithium-ion battery anodes