The mechanism of paeoniflorin binding to calf thymus DNA in physiological buffer (pH 7.4) was investigated by multispectroscopic methods including UV–vis absorption, fluorescence, circular dichroism ...(CD) and Fourier transform infrared (FT-IR) spectroscopy, coupled with viscosity measurements and DNA melting techniques. The results suggested that paeoniflorin molecules could bind to DNA via groove binding mode as evidenced by no significant change in iodide quenching effect, increase in single-stranded DNA (ssDNA) quenching effect, and almost unchanged relative viscosity and melting temperature of DNA. The observed changes in CD signals revealed that DNA remains in the B-conformation. Further, the displacement experiments with Hoechst 33258 probe and the results of FT-IR spectra indicated that paeoniflorin mainly binds in the region of rich A–T base pairs of DNA. The thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°) were calculated to be –30.09±0.18kJmol−1 and –14.07±0.61Jmol−1K−1 by the van't Hoff equation, suggesting that hydrogen bond and van der Waals forces play a predominant role in the binding of paeoniflorin to DNA.
► The binding mode of paeoniflorin to calf thymus DNA is the minor groove binding. ► Paeoniflorin mainly binds in the region of rich A–T base pairs of DNA. ► The binding does not alter the native B-conformation of DNA. ► The binding is driven mainly by hydrogen bonds and van der Waals forces.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Highly photoactive Ti-doped FeVO4 photoanodes with ordered nanoblock morphology were prepared by drop-casting mixed Ti and V precursors onto FeOOH nanorod films and following an annealing process for ...photoelectrochemical water splitting.
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•A novel crystalline Ti-doped FeVO4 photoelectrodes is developed.•Ti4+ is uniformly doped by substituting V5+ and increases O2– vacancies.•T-FVO shows a state-of-the-art photocurrent value of ~ 1.47 mA cm−2.•Ti-doping remarkably enhances charge carrier concentration and conductivity.•Ti-doping facilitates charge transfer kinetics at the interface.
Highly photoactive FeVO4 photoanodes with ordered nanoblock morphology and uniform Ti-doping were prepared by drop-casting mixed Ti and V precursors onto FeOOH nanorod films and following an annealing process. The results indicate that Ti4+ is uniformly doped into the FeVO4 lattice by substituting V5+ and provides an increased number of O2– vacancies. The optimized film thickness and doping level are 620 nm and 0.3%, respectively. Compared to the undoped sample, the Ti-doped photoanode showed ~ 219% enhancement in photocurrent at 1.0 V vs Ag/AgCl under back illumination of AM 1.5, reaching a state-of-the-art value of ~ 1.47 mA cm−2, and also achieved stable and efficient overall water splitting activity with evolution rates of 28.3 and 14.1 μmol cm−2h−1 for H2 and O2, respectively. The excellent PEC performance could be attributed to the remarkably enhanced charge carrier concentration and conductivity, and the facilitated charge transfer kinetics across the semiconductor/electrolyte interface, as a result of Ti-doping.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Developing a semiconductor-based heterostructure photoanode is crucial in improving the photoelectrocatalytic (PEC) efficiency for degrading refractory organic pollutants. Nevertheless, the PEC ...performance of the photoanodes is usually restricted by electron/hole pair recombination, oxygen evolution, and slow electron transfer. Herein, a novel CoO@BiVO
nanowire array film (Ti/CoO@BiVO
) with n-type semiconductor characteristics was prepared via a straightforward hydrothermal method. The optimized Ti/CoO@BiVO
electrode exhibited excellent PEC decolorization efficiency of active brilliant blue KN-R (∼92.8%) and long-term stability, outperforming recent reports. The insight reason for enhancing the PEC degradation efficiency of the Ti/CoO@BiVO
electrodes can be attributed to the large electrochemical active area, low charge transfer resistance, and negative flat band potential. The formation of a type-II heterostructure was investigated between CoO and BiVO
further to promote the generation and separation efficiency of electron/hole pairs, indicating that the optimized Ti/CoO@BiVO
electrode has the potential for the water PEC degradation ability and superior service life.
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IJS, KILJ, NUK, PNG, UL, UM
Model Predictive Control (MPC) has been demonstrated to be an efficient way to reduce building operating costs, especially for buildings with thermal storage systems, by changing the power demand ...profiles. Different parameter settings of MPC have also been shown to have significant influence on building power usage, which may therefore influence building demand flexibility. In this study, we estimate how MPC parameters such as the prediction horizon (PH) can influence building demand flexibility. A virtual high-fidelity building testbed was created in Modelica based on actual measurement data from a chiller plant with an ice storage tank system. Then the virtual system was randomly perturbed to generate training data for the MPC models. The MPC was formulated as a nonlinear programming problem and solved using a global optimization solver. We found that MPC can reduce operating costs by 15.8 % and reduce the peak power demand by 24.8 % compared with rule-based storage-priority control. The building demand flexibility initially increases as the PH increases and then reaches its plateau when the PH is longer than 20-hours. Evaluation of the building demand flexibility will provide insights into choosing the suitable MPC formulation for a grid-interactive efficient building.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
AbstractThe chloride content is a critical factor influencing the corrosion of steel fibers in concrete. This study focused on the corrosion behaviors of steel fibers exposed to simulated concrete ...pore solutions with different chloride contents. The corrosion rates of the steel fibers were calculated based on the changes in the diameter and ultimate tensile load. The electrochemical parameters for the corrosion of the steel fibers were continuously monitored for 62 days. In addition, the surface micromorphologies of the corroded steel fibers were observed using scanning electron microscopy (SEM). The results showed that based on the change in the diameter, the corrosion rate of the steel fibers increased almost linearly when the NaCl content in the simulated solution increased from 2% to 5%. However, based on the variation of the ultimate tensile load, the corrosion ratio of the steel fibers increased linearly with the increase in the exposure time when the NaCl content was less than 3%, while it increased exponentially when the NaCl content exceeded 3%. According to the open circuit potential, Tafel polarization curves, and electrochemical impedance spectroscopy (EIS), the corrosion tendency and corrosion rates of the steel fibers exposed to the simulated solutions increased significantly when the NaCl content increased from 2% to 5%. Additionally, the corrosion damage on the surfaces of the steel fibers increased notably, and after 180 days of exposure to the simulated solution with 5% NaCl, the steel fiber was almost broken. These findings will help to understand the durability of SFRC in a chloride environment.
Developing efficient, stable, and user-friendly adsorbents for removing uranium from radioactive wastewater is critical for ensuring the security of nuclear energy development. Here, a fixed ...adsorbent (nZVI@NC/CF), composed of in-situ derived N-doped carbon (NC) encapsulated nano zero-valent iron (nZVI) coated on carbon fiber (CF), was synthesized via carbonizing Prussian blue decorated CF, and used to synergistically adsorb and reduce UO22+ from contaminated water. The optimized nZVI@NC/CF exhibited an extremely high adsorption capacity of 2120.27 mg g−1 with a superior adsorption rate, and about 56.8 % fixed uranium was reduced into insoluble U(IV) species. This outstanding adsorption activity could be ascribed to the strong reducing property of nZVI and the package of NC that effectively prevented the agglomeration of nZVI and facilitated the adsorption and reduction of UO22+ due to the rich adsorption sites and good charge transport property. The nZVI@NC/CF also showed excellent anti-interference properties and regeneration performance that exhibited great potential in treating real uranium wastewater and extracting uranium from seawater. Mechanism study revealed that the fixation of UO22+ was mainly achieved through the synergistical adsorption by NC and reduction by nZVI, complexation by hydroxyl groups, and hydrolytic precipitation by local OH−. This study underscores the potential of nZVI@NC/CF as a highly effective adsorbent material, and provides valuable insights into developing efficient, stable, and easily manageable materials for uranium recovery.
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•A novel fixed adsorbent (nZVI@NC/CF) is synthesized via carbonizing PB decorated CF.•NZVI is encapsulated by NC and coated on CF, preventing its agglomeration and facilitating U removal.•An adsorption capacity of 2120.27 mg g−1 is achieved and 56.8 % of U is reduced into U(IV).•Excellent anti-interference properties and regeneration performance are also obtained.•Mechanism includes adsorption by NC, reduction by nZVI, complexation by –OH, and precipitation by OH−.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Microplastics (MPs) are small plastic pieces less than 5 mm in size. Previous studies have focused on the sources, transports, and fates of MPs in marine or sediment environments. However, limited ...attention has been given to the role of land as the primary source of MPs, and how plastic polymers are transformed into MPs through biological or abiotic effects during the transport process remains unclear. Here, we focus on the exploration of the main sources of MPs in the soil, highlighting that MP generation is not solely a byproduct of plastic production but can also result from the impact of biological and abiotic factors during the process of MPs transport. This review presents a new perspective on understanding the degradation of MPs in soil, considering soil as a distinct fluid and suggesting that the main transformation and change mediated by abiotic factors occur on the soil surface, while the main biodegradation occurs in the soil interior. This viewpoint is suggested because the role of some abiotic factors becomes less obvious in the soil interior, and MPs, whose surface is expected to colonize microorganisms, are gradually considered a carbon source independent of photosynthesis and net primary production. This review emphasizes the need to understand basic MPs information in soil for a rational evaluation of its environmental toxicity. Such understanding enables better control of MPs pollution in affected areas and prevents contamination in unaffected regions. Finally, knowledge gaps and future research directions necessary for advancements in this field are provided.
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•Microplastic pollution is of growing concern as it accumulates in the soil.•The transport of microplastic from source to destination is an imperative study.•Plastic is transformed into microplastic through biological or abiotic effects.•Native microbiota may possess the ability for in situ bioremediation.•Microplastic degradation by anaerobic microbiota is interesting to investigate.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The design of zein-based nanoparticles to encapsulate bioactive molecules has gained great attention in recent years. However, the use of ethanol to dissolve zein presents flammability concerns and ...the scale-up production of zein-based nanoparticles is also a concern. In our study, propolis loaded zein/caseinate/alginate nanoparticles were fabricated using a facile one-step procedure: a well-blended solution was prepared containing deprotonated propolis, soluble zein, dissociated sodium caseinate micelles (NaCas) and alginate at alkaline pH, and then this alkaline solution was added to 0.1 M citrate buffer (pH 3.8) to fabricate composite nanoparticles without using organic solvents and sophisticated equipment. During acidification, the alginate molecules adsorbed on the zein/NaCas surfaces by electrostatic complexation, which improved the stability towards aggregation of zein/NaCas nanoparticles under gastrointestinal (GI) or acidic pH. The nanoparticles prepared under the optimized method (method 3 sample) were of spherical morphology with a particle size around 208 nm and a negative zeta potential around -27 mV. The encapsulation efficiency (EE) and loading capacity (LC) of propolis reached 86.5% and 59.6 μg mg-1 by zein/NaCas/alginate nanoparticles, respectively. These nanoparticles were shown to be stable towards aggregation over a wide range of pH values (2-8) and salt concentrations (0-300 mM NaCl). Compared to free propolis, the bioaccessibility of propolis encapsulated with nanoparticles was increased to 80%. Our results showed a promising clean and scalability strategy to encapsulate hydrophobic nutraceuticals for applications in foods, supplements, and pharmaceuticals.
The construction of a desirable, environmentally friendly, and cost-effective nanoheterostructure photoanode to treat refractory organics is critical and challenging. Herein, we unveiled a ...hierarchical dendritic Co
O
-SnO
heterostructure via a sequential hydrothermal process. The time of the secondary hydrothermal process can control the size of the ultrathin SnO
nanosheets on the basis of the Ostwald solidification mass conservation principle. Ti/Co
O
-SnO
-168h with critical growth size demonstrated a photoelectrocatalysis degradation rate of ∼93.3% for a high dye concentrate of 90 mg/L with acceptable long-term cyclability and durability over reported Co
O
-based electrodes because of the large electrochemically active area, low charge transfer resistance, and high photocurrent intensity. To gain insight into the photoelectric synergy, we proposed a type-II heterojunction between Co
O
and SnO
, which prevents photogenerated carriers' recombination and improves the generation of dominant active species •O
,
O
, and h
. This work uncovered the Ti/Co
O
-SnO
-168 as a promising catalyst and provided a simple and inexpensive assembly strategy to obtain binary integrated nanohybrids with targeted functionalities.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
The tuning of band gap is very important for the application of two-dimensional (2D) materials in optoelectronic devices. Alloying of 2D transition metal dichalcogenides (TMDCs) is an ...important way to tune the wide band gap. In this study, we report a multi-step vapor deposition method to grow monolayer TMDC ternary alloy films with wafer scale, including Mo
1−
x
W
x
S
2
, Mo
1−
x
W
x
Se
2
and MoS
2
x
Se
2(1−
x
)
, which are accurately controllable in the elemental proportion (
x
is from 0 to 1). The band gap of the three 2D ternary alloy materials are continuously tuned for the whole range of metal and chalcogen compositions. The metal compositions are controlled by the as-deposited thickness. Raman, photoluminescence, elemental maps and TEM show the high spatial homogeneity in the compositions and optical properties across the whole wafer. The band gap can be continuously tuned from 1.86 to 1.99 eV for Mo
1−
x
W
x
S
2
, 1.56 to 1.65 eV for Mo
1−
x
W
x
Se
2
, 1.56 to 1.86 eV for MoS
2
x
Se
2(1−
x
)
. Electrical transport measurements indicate that Mo
1−
x
W
x
S
2
and MoS
2
x
Se
2(1−
x
)
monolayers show
n
-type semiconductor behaviors, and the carrier types of Mo
1−
x
W
x
Se
2
can be tuned as
n
-type, bipolar and
p
-type. Moreover, this control process can be easily generalized to other 2D alloy films, even to quaternary or multi-element alloy materials. Our study presents a promising route for the preparation of large-scale homogeneous monolayer TMDC alloys and the application for future functional devices.