One injection for one-week controlled release: In vitro and in vivo assessment of ultrasound-triggered drug release from injectable thermoresponsive biocompatible hydrogels

Episodic release of bioactive compounds is often necessary for appropriate biological effects under specific physiological conditions. Here, we aimed to develop an injectable, biocompatible, and thermosensitive hydrogel system for ultrasound (US)-triggered drug release. An mPEG-PLGA-BOX block copolymer hydrogel was synthesized. The viscosity of 15 wt% hydrogel is 0.03 Pa*s at 25 °C (liquid form) and 34.37 Pa*s at 37 °C (gel form). Baseline and US-responsive in vitro release profile of a small molecule (doxorubicin) and that of a large molecule (FITC-dextran), from the hydrogel, was tested. A constant baseline release was observed in vitro for 7 d. When triggered by US (1 MHz, continuous, 0.4 W/cm²), the release rate increased by approximately 70 times. Without US, the release rate returned to baseline. Baseline and US-responsive in vivo release profile of doxorubicin was tested by subcutaneous injection in the back of mice and rats. Following injection into the subcutaneous layer, in vivo results also suggested that the hydrogels remained in situ and provided a steady release for at least 7 d; in the presence of the US-trigger, in vivo release from the hydrogel increased by approximately 10 times. Therefore, the mPEG-PLGA-BOX block copolymer hydrogel may serve as an injectable, biocompatible, and thermosensitive hydrogel system that is applicable for US-triggered drug release.     

conversion electron Mössbauer study of low carbon steel polarized in aqueous sulfate solution containing sulfite in low concentration

The passivation of low carbon steel was studied in aqueous solution of 0.5 M Na₂SO₄+0.001 M NaHSO₃ at pH=3.5 and 6.5. The found major components at pH-3.5 were: γ-FeOOH and Fe₃C, and also FeSO₄.H₂O could be identified on the surface of the low carbon steel as a minor component. At pH-6.5, the passive film contained only amorphous iron(III)-oxide or oxyhydroxide.     

Atmospheric oxidation chemistry of 1–methoxy 2–propyl acetate initiated by OH radicals: kinetics and mechanisms

Kinetics and mechanism of the gas-phase reaction of CH₃C(O)OCH(CH₃)CH₂OCH₃ (MPA) with OH radicals in the presence of O₂ and NO have been investigated theoretically by performing a high and reliable level of theory, viz., CCSD(T)/6-311?+?G(d,p)//BH&HLYP/6-311++G(d,p)?+?0.9335×ZPE. The calculations predict that the H-abstraction from the ?CH₂?O? position of MPA is the most facile channel, which leads to the formation of the corresponding alkoxy radicals CH₃C(O)OCH(CH₃)C(O ?)HOCH₃ under atmospheric conditions. This activated radicals CH₃C(O)OCH(CH₃)C(O ?)HOCH₃ will undergo further rearrangement, fragmentation and oxidative reactions and predominantly leads to the formation of various products (methyl formate HC(O)OCH₃ and acetic anhydride CH₃C(O)OC(O)CH₃). In the presence of water, acetic anhydride can convert into acetic acid CH₃C(O)OH via the hydrolysis reaction. The calculated total rate constants over the temperature range 263–372?K are used to derive a negative activation energy (E_a= ?5.88 kJ/mol) and an pre-exponential factor (A?=?1.78×10^?12 cm³ molecule^?1 s^?1). The obtained Arrhenius parameters presented here are in strong agreement with the experimental values. Moreover, the temperature dependence of the total rate constant over a temperature range of 263?1000?K can be described by k?=?5.60 × 10^?14×(T/298?K)^3.4×exp(1725.7?K/T) cm³ molecule^?1 s^?1.     

Correlation of Diffusional Exponent with Structural Sequence of (N-Vinylpyrrolidone-alt-Acrylic Acid) Hydrogels: A Predictive Hydrogel Design Approach

Correlation of diffusional exponent of water into (N-Vinylpyrrolidone-alt-Acrylic acid) hydrogels with the structural sequence of hydrogel repeating units (i.e. hydrophilic and/or hydrophobic moieties) through a scaling law relationship has been investigated. The diffusional exponent (n) was found to depend linearly on Y/X² , where X equals to molar ratio of monomers in the feed (i.e. ([M₁ ]/[M₂ ])_feed) and Y equals to molar ratio of repeating units in the copolymer (i.e. ([M₁ ]/[M₂ ])_copolymer). Copolymers rich in hydrophilic acrylic acid (i.e. larger Y/X² ) were found to form more coiled polymeric chains as acrylic acid content increased due to H-bonding interactions, and hence results in lower diffusion coefficients and linear lowering of the n-value. On the other hand copolymers rich in partially hydrophobic N-vinylpyrrolidone (i.e. smaller Y/X²) formed more uncoiled polymeric chains as N-vinylpyrrolidone content increased due to larger amounts of positively charged protonated nitrogen atoms at pH 5.5 that tend to repel each other, which eventually lead to higher diffusion coefficients and a linear increase in n-value. These characteristic findings could be significant in sustained drug release studies, where the structural sequence of a hydrogel plays a dominant role in the release kinetics of a drug at certain positions and/or times.     

Ultrasound stimulated release of mimosa medicine from cellulose hydrogel matrix

Ultrasound (US) drug release system using cellulose based hydrogel films was developed as triggered to mimosa. Here, the mimosa, a fascinating drug to cure injured skin, was employed as the loading drug in cellulose hydrogel films prepared with phase inversion method. The mimosa hydrogels were fabricated from dimethylacetamide (DMAc)/LiCl solution in the presence of mimosa, when the solution was exposed to ethanol vapor. The US triggered release of the mimosa from the hydrogel matrix was carried out under following conditions of US powers (0–30 W) and frequencies (23, 43 and 96 kHz) for different mimosa hydrogel matrix from 0.5 wt% to 2 wt% cellulose solution. To release the drug by US trigger from the matrix, the better medicine release was observed in the matrix prepared from the 0.5 wt% cellulose solution when the 43 kHz US was exposed to the aqueous solution with the hydrogel matrix. The release efficiency increased with the increase of the US power from 5 to 30 W at 43 kHz. Viscoelasticity of the hydrogel matrix showed that the hydrogel became somewhat rigid after the US exposure. FT-IR analysis of the mimosa hydrogel matrixes showed that during the US exposure, hydrogen bonds in the structure of mimosa–water and mimosa–cellulose were broken. This suggested that the enhancement of the mimosa release was caused by the US exposure.     

Structure and dynamics of CH2O,OH, and the velocity field of a confined bluff-body premixed flame,using simultaneous PLIF and PIV at 10 kHz.

This study characterizes the structure and dynamics of a confined, bluff-body-stabilized turbulent premixed flame by simultaneously employing formaldehyde (CH₂O) and hydroxyl (OH) planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV), at a rate of 10?kHz. The large field-of-view (>170 cm²) CH₂O-PLIF is enabled by use of a burst-mode laser delivering 10-kHz pulse trains of 355-nm at 350 mJ/pulse, resulting in a CH₂O signal-to-noise of 47:1 during PIV seed flow. Two cases illustrative of the CH₂O dynamics are presented. A statistically stationary turbulent combustion case highlights the development of the CH₂O layers in space and time. Notably, presumed CH₂O-vortex dynamic interactions are observed where the CH₂O accumulates broadly near the Kelvin–Helmholtz vortex core and remains thin near the vortex braid, contributing to a distribution of CH₂O preheat zone thickness from 1 to 10 times of the calculated laminar value. The second case highlights the CH₂O dynamics during a self-excited combustion instability. Two short-duration increases in CH₂O are produced during the elevated velocity portion of the acoustic cycle. The first CH₂O increase is caused by the reactant mass flux impulse as the velocity starts to increase. The second CH₂O increase is the result of the upper and lower shear layers merging downstream and entraining fresh reactants that burn in intense, distributed regions inside the wake. Estimating the time delay between the CH₂O and the heat release, it is suggested that the secondary CH₂O increase may contribute to damping of the acoustic instability, because of its out-of-phase relationship with pressure, while the first CH₂O increase appears to drive the instability.     

Regulating the thermal response of PNIPAM hydrogels by controlling the adsorption of magnetite nanoparticles

Thermoswitchable magnetic hydrogels are being extensively investigated because of their great potential for medical applications. Indeed, they can behave as smart carriers able to transport drugs to a chosen part of the body and release them via magneto-thermal activation by an external alternating magnetic field. We report on the magnetization of the thermosensitive poly(N-isopropylacrylamide) hydrogel through the adsorption of controlled amounts of magnetite nanoparticles. We show that the temperature at which the hydrogel contraction occurs (i.e. the lower critical solution temperature) can be controlled from 32 ^°C to 52 ^°C by varying the concentration of adsorbed nanoparticles. This is clearly shown by photon correlation spectroscopy. The results are an advance in the use of the magnetized poly(N-isopropylacrylamide) hydrogel as a flexible and adjustable nanomaterial and are of great interest in numerous applications which require drug release on demand.     

Controlled release of ketorolac through nanocomposite films of hydrogel and LDH nanoparticles

A novel nanocomposite film for sustained release of anionic ophthalmic drugs through a double-control process has been examined in this study. The film, made as a drug-loaded contact lens, consists principally of a polymer hydrogel of 2-hydroxyethyl methacrylate (HEMA), in whose matrix MgAl-layered double hydroxide (MgAl-LDH) nanoparticles intercalated with the anionic drug are well dispersed. Such nanocomposite films (hydrogel-LDH-drug) contained 0.6–0.8 mg of MgAl-LDH and 0.08–0.09 mg of the ophthalmic drug (ketorolac) in 1.0 g of hydrogel. MgAl-drug-LDH nanoparticles were prepared with the hydrodynamic particle size of 40–200 nm. TEM images show that these nanoparticles are evenly dispersed in the hydrogel matrix. In vitro release tests of hydrogel-LDH-drug in pH 7.4 PBS solution at 32 °C indicate a sustained release profile of the loaded drug for 1 week. The drug release undergoes a rapid initial burst and then a monotonically decreasing rate up to 168 h. The initial burst release is determined by the film thickness and the polymerization conditions, but the following release rate is very similar, with the effective diffusion coefficient being nearly constant (3.0 × 10⁻¹² m²/s). The drug release from the films is mechanistically attributed to anionic exchange and the subsequent diffusion in the hydrogel matrix.     

The catalytic effects of H2CO3, CH3COOH,HCOOH and H2O on the addition reaction of CH2OO + H2O → CH2(OH)OOH

The addition reaction of CH₂OO + H₂O → CH₂(OH)OOH without and with X (X = H₂CO₃, CH₃COOH and HCOOH) and H₂O was studied at CCSD(T)/6-311+ G(3df,2dp)//B3LYP/6-311+G(2d,2p) level of theory. Our results show that X can catalyse CH₂OO + H₂O → CH₂(OH)OOH reaction both by increasing the number of rings, and by adding the size of the ring in which ring enlargement by COOH moiety of X inserting into CH₂OO···H₂O is favourable one. Water-assisted CH₂OO + H₂O → CH₂(OH)OOH can occur by H₂O moiety of (H₂O)₂ or the whole (H₂O)₂ forming cyclic structure with CH₂OO, where the latter form is more favourable. Because the concentration of H₂CO₃ is unknown, the influence of CH₃COOH, HCOOH and H₂O were calculated within 0–30 km altitude of the Earth's atmosphere. The results calculated within 0–5 km altitude show that H₂O and HCOOH have obvious effect on enhancing the rate with the enhancement factors are, respectively, 62.47%–77.26% and 0.04%–1.76%. Within 5–30 km altitude, HCOOH has obvious effect on enhancing the title rate with the enhancement factor of 2.69%–98.28%. However, compared with the reaction of CH₂OO + HCOOH, the rate of CH₂OO···H₂O + HCOOH is much slower.     

The autocatalytic decomposition of acetic acid on Ni(110)

The flash decomposition of CH₃COOH was studied on a clean nickel (110) surface following adsorption at 30° C in order to access the applicability of chemical reaction rate theory to a homologous series of reactants on a well-defined surface. As was observed for formic acid, acetic acid adsorbed at 30° C to yield gaseous H₂O and to form islands of adsorbed anhydride intermediates; the decomposition proceeded by a two-dimensional auto-catalytic mechanism to form H₂, CO₂, Co and surface carbon. The decomposition of the anhydride was rate determining for the formation of CO₂ and H₂. The rate of decomposition was well described by the equation governing the formic acid decomposition on the same surface. The activation energy for this first order decomposition was determined to be 28.2 $\text{kcal}\text{gmol}$ and the pre-exponential factor, v, was found to be 6.4 × 10¹⁴ s^?1 with a fraction of initiation sites of 0.004. These values were nearly the same as those observed for the decomposition of HCOOH, suggesting identical intramolecular mechanisms for the unimolecular decomposition of the adsorbed intermediates. The relative values of v for the decomposition of HCOOH, DCOOH and CH₃COOH indicated that the motion of the H, D or CH₃ group was involved in the rate-limiting step.     

Preparation and Properties of Polyurethane Hydrogels Based on Methylene Diphenyl Diisocyanate/Polycaprolactone-Polyethylene Glycol

Polyurethane (PU) hydrogel is an important biomedical material for drug controlled release systems, wound dressings and medical bandages. Three series of polyurethane prepolymers based on methylene diphenyl diisocyanate (MDI), polycaprolactone (PCL) and polyethylene glycol (PEG), using diethylene glycol (DEG), N-methyldiethanolamine (MDEA) or dimethylolpropionic acid (DMPA), as the chain-extender, were prepared. Then the polyurethane hydrogels were obtained from the prepolymers, using benzoyl peroxide (BPO) as a cross-linking agent, by free radical polymerization. The influences of the types of chain-extenders and polyols on the contact angle, swelling ratio and morphology of the polyurethane hydrogels were investigated. The effect of the variety of the chain-extenders in the PU hydrogel on the drug release behavior was also studied. The FT-IR results showed that the PU hydrogels were successfully synthesized. The introduction of PEG improved the hydrophilicity of the PU hydrogels. The MDI/PCL-PEG/DEG hydrogel was hydrophobic, and there were small micropores on its surface; while the MDI/PCL-PEG/DMPA and MDI/PCL-PEG/MDEA hydrogels had high hydrophilicity and a micropouous structure on their surface due to the existence of carboxyl and tertiary amino functional groups. The change of chain-extenders had no significant effect on the cumulative drug release of chloramphenicol from the PU hydrogels. However, the introduction of PEG increased the drug release rate. The chloramphenicol release kinetics from the MDI/PCL-PEG hydrogels indicated non-Fickian diffusion.     

多溶剂响应自折叠水凝胶

本文基于寡聚乙二醇甲醚甲基丙烯酸酯(OEGMA)和2-甲基-2-丙烯酸-2-(2-甲氧基乙氧基)乙酯(MEO₂MA)设计了一种自折叠水凝胶. 在室温下,P(MEO₂MA-co-OEGMA)凝胶能够在多种溶剂中自折叠形成三维结构. 凝胶不均匀膨胀导致内应力增强,从而使得片状凝胶可以在三维结构和二维形状之间进行可逆转换. 研究表明,凝胶组成、固化气体环境和成型过程对水凝胶的自折叠过程起着重要的影响.     

The microwave spectrum of methylene ketene

The microwave spectrum of methylene ketene has been observed from 8 to 35 GHz and assigned. Rotational constants and centrifugal distortion constants have been determined for CH₂CCO, CHDCCO, and CD₂CCO. The dipole moment was found to be μ_a = 2.14 ± 0.06 D (7.07 ± 0.2 × 10^?30 Cm). We were unable to detect propynal among the pyrolysis products of acrylic anhydride. This pyrolysis proved to be the most convenient route for generating methylene ketene for the present investigation.     

Theoretical study on the reactions of CH3NHNH2 with ground state O(3P) atom and excited state O(1D) atom

The reaction mechanisms of methylhydrazine (CH₃NHNH₂) with O(³P) and O(¹D) atoms have been explored theoretically at the MPW1K/6-311+G(d,p), MP2/6-311+G(d,p), MCG3-MPWPW91 (single-point), and CCSD(T)/cc-pVTZ (single-point) levels. The triplet potential energy surface for the reaction of CH₃NHNH₂ with O(³P) includes seven stable isomers and eight transition states. When the O(³P) atom approaches CH₃NHNH₂, the heavy atoms, namely N and C atoms, are the favourable combining points. O(³P) atom attacking the middle-N atom in CH₃NHNH₂ results in the formation of an energy-rich isomer (CH₃NHONH₂) followed by migration of O(³P) atom from middle-N atom to middle-H atom leading to the product P6 (CH₃NNH₂+OH), which is one of the most favourable routes. The estimated major product CH₃NNH₂ is consistent with the experimental measurements. Reaction of O(¹D) + CH₃NHNH₂ presents different features as compared with O(³P) + CH₃NHNH₂. O(¹D) atom will first insert into C–H2, N1–H4, and N2–H5 bonds barrierlessly to form the three adducts, respectively. There are two most favourable paths for O(¹D) + CH₃NHNH₂. One is that the C–N bond cleavage accompanied by a concerted H shift from O atom to N atom (mid-N) leads to the product P_I (CH₂O + NH₂NH₂), and the other is that the N–N bond rupture along with a concerted H shift from O to N (end-N) forms P_IV (CH₃NH₂ + HNO). The similarities and discrepancies between two reactions are discussed.     

A DFT study on the formation of CH3O on Cu2O(1 1 1) surface by CH3OH decomposition in the absence or presence of oxygen

The formation mechanism of CH₃O by the adsorption and decomposition of CH₃OH on clean and oxygen-precovered Cu₂O(1 1 1) surface has been investigated with density functional theory method together with the periodic slab models. Two possible formation pathways of CH₃O by CH₃OH decomposition on oxygen-precovered (O_pre) Cu₂O(1 1 1) surface were proposed and discussed. One is the O-H bond-cleavage of CH₃OH with H migration to O_pre to form CH₃O; the other is the C-O bond-scission of CH₃OH with CH₃ migration to O_pre leading to CH₃O_pre. The calculated results show that the O-H bond-breaking path has the lowest activation barrier 26.8 kJ mol⁻¹, the presence of oxygen-precovered on Cu₂O(1 1 1) surface exhibits a high surface reactivity toward the formation of CH₃O by the O-H bond-cleavage of CH₃OH, and reduce the activation barrier of O-H bond-cleavage. The C-O bond-breaking path was inhibited by dynamics, suggesting that the O atom of CH₃O is not from the oxygen-precovered, but comes from the O of CH₃OH. Meanwhile, the calculated results give a clear illustration about the formation mechanism of CH₃O in the presence of oxygen and the role of oxygen at the microscopic level.     

Temperature and magnetic field responsive hyaluronic acid particles with tunable physical and chemical properties

We report the preparation and characterization of thiolated-temperature-responsive hyaluronic acid-cysteamine-N-isopropyl acrylamide (HA-CYs-NIPAm) particles and thiolated-magnetic-responsive hyaluronic acid (HA-Fe-CYs) particles. Linear hyaluronic acid (HA) crosslinked with divinyl sulfone as HA particles was prepared using a water-in-oil micro emulsion system which were then oxidized HA-O with NaIO₄ to develop aldehyde groups on the particle surface_. HA-O hydrogel particles were then reacted with cysteamine (CYs) which interacted with aldehydes on the HA surface to form HA particles with cysteamine (HA-CYs) functionality on the surface. HA-CYs particles were further exposed to radical polymerization with NIPAm to obtain temperature responsive HA-CYs-NIPAm hydrogel particles. To acquire magnetic field responsive HA composites, magnetic iron particles were included in HA to form HA-Fe during HA particle preparation. HA-Fe hydrogel particles were also chemically modified. The prepared HA-CYs-NIPAm demonstrated temperature dependent size variations and phase transition temperature. HA-CYs-NIPAm and HA-Fe-CYs particles can be used as drug delivery vehicles. Sulfamethoxazole (SMZ), an antibacterial drug, was used as a model drug for temperature-induced release studies from these particles.     

Electric field gradients in PrBa2 Cu 3 O 7 : LSDA+U results and comparison with experiment

Electric-field gradient (EFG) and asymmetry parameter (η) at all oxygen and copper sites of nonsuperconducting PrBa₂Cu₃O₇ (Pr123) compound were calculated using the full-potential (linearized)-augmented-plane-wave plus local orbitals method. Exchange and correlation effects were treated by LSDA+U for Cu(3d) and Pr(4f) electrons. The effects of changing screened Coulomb parameters U_Pr, U_Cu1, and U_Cu2 on the results were individually studied. The calculated EFG of O2 site is close to the EFG of O3 site at variance with the experimental result. It was shown that by increasing superconducting holes in O2 and O3 sites the EFG at these sites increase and vice versa. The most famous theories which have been proposed to explain the suppression of superconductivity in perfect (without any mis-substitution or other defects) Pr123 compound are not consistent with the experimental EFG at O2 and O3 sites. By replacing one Pr atom at the Ba site on unit cell of Pr123 (Pr_Ba), it was shown that Pr_Ba mis-substitution reduces the superconducting holes in both O2 and O3 sites and could be responsible for the suppuration of superconductivity in Pr123 samples. It is very probable that the unusual behaviors of experimental EFG at O2 and O3 sites of Pr123 are related to oxygen defects which are produced with Pr_Ba mis-substitution.     

A comprehensive study of (CH3)2CHOC(S)SC(O)OCH3 using matrix isolation technique,X‐ray analysis,spectroscopic studies and theoretical calculations

Potassium isopropyl xanthate, (CH₃)₂CHOC(S)SK, reacts with methyl chloroformiate ClC(O)OCH₃ to yield (methoxycarbonyl) (2‐propoxythiocarbonyl) sulfide, (CH₃)₂CHOC(S)SC(O)OCH₃. This novel xanthogen formate was characterized by ¹H and ¹³C{¹H} NMR spectroscopy, mass spectrometry and IR and Raman spectroscopy. The structure of a single crystal of (CH₃)₂CHOC(S)SC(O)OCH₃ was determined by X‐ray diffraction analysis at 173 K. The conformational properties have been studied by liquid IR and Raman spectroscopy, matrix isolation spectroscopy together with photochemical studies and quantum chemical calculations (HF and B3LYP methods with the 6‐31+G* basis set). The analysis of the IR spectrum of liquid (CH₃)₂CHOC(S)SC(O)OCH₃ suggests the presence of two conformers in equilibrium at room temperature. However, in the photochemical matrix study, an equilibrium of three conformers was detected. These forms were further characterized by theoretical calculations. Different photolysis products, such as CH₃OC(O)SCH(CH₃)₂, OCS, CO, CO₂ and CS₂, were identified by matrix spectroscopy. The IR absorptions of CH₃OC(O)SCH(CH₃)₂, for which literature data are scarce, were analysed in the light of the results of appropriate theoretical calculations. Copyright © 2009 John Wiley & Sons, Ltd.     

Facile Preparation of Core-Shell Nanocomposite Microgels

Microgels with alginate (Alg) gel cores and shells of SiO₂ nanoparticles (so-called colloidosomes) were prepared by self-assembly of SiO₂ nanoparticles at ALG aqueous solution–hexane interfaces and subsequent in situ gelation caused by Ca²⁺ ions that were released from calcium-ethylenediamine tetraacetic acid chelate by decreasing the pH value through the slow hydrolysis of D-Gluconic-δ-lactone. The packing density of SiO₂ nanoparticles in the shell was about 0.906, indicating that the SiO₂ nanoparticles were present monolayer on the surfaces of the colloidosomes. The half release times of insulin microcrystals were 4 h for Alg gel microspheres and 10 h for Alg/SiO₂ colloidosomes at pH 7.4, compared to 1.5 h for bare insulin. The half release times of insulin microcrystals were 12 min for Alg gel microspheres and 30 min for Alg/SiO₂ colloidosomes at pH 1.2, compared to 30 s for bare insulin. The release rates of insulin from the colloidosomes with core–shell structure were slower than that from bare insulin crystals due to the dual barriers of the hydrogel cores and the close-packed inorganic shells. The release curves were nicely fitted by the Weibull equation and the release followed Fickian diffusion.     

CH3OH在ZnO(0001)表面的光催化解离

本文利用266 nm波长的激光及程序升温脱附的方法研究了甲醇在ZnO(0001)表面的光催化反应. TPD结果显示部分的CH₃OH以分子的形式吸附在ZnO(0001)表面,而另外一部分在表面发生了解离. 实验过程中探测到H₂,CH₃^·,H₂O,CO,CH₂O,CO₂和CH₃OH这些热反应产物. 紫外激光照射实验结果表明光照可以促进CH₃OH/CH₃O^·解离形成CH₂O,在程序升温或光照的过程中它又可以转变为HCOO^-. CH₂OH_Zn与OH_ad反应在Zn位点上形成H₂O分子. 升温或光照都能促进CH₃O^·转变为CH₃^·. 该研究对CH₃OH在ZnO(0001)表面的光催化反应机理提供了一个新的见解.