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1.
Int J Mol Sci ; 25(11)2024 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-38891987

RESUMO

Alginate lyases cleave the 1,4-glycosidic bond of alginate by eliminating sugar molecules from its bond. While earlier reported alginate lyases were primarily single catalytic domains, research on multi-module alginate lyases has been lfiguimited. This study identified VsAly7A, a multi-module alginate lyase present in Vibrio sp. QY108, comprising a "Pro-Asp-Thr(PDT)" fragment and two PL-7 catalytic domains (CD I and CD II). The "PDT" fragment enhances the soluble expression level and increases the thermostability and binding affinity to the substrate. Moreover, CD I exhibited greater catalytic efficiency than CD II. The incorporation of PDT-CD I resulted in an increase in the optimal temperature of VsAly7A, whereas CD II displayed a preference for polyG degradation. The multi-domain structure of VsAly7A provides a new idea for the rational design of alginate lyase, whilst the "PDT" fragment may serve as a fusion tag in the soluble expression of recombinant proteins.


Assuntos
Alginatos , Estabilidade Enzimática , Polissacarídeo-Liases , Vibrio , Polissacarídeo-Liases/metabolismo , Polissacarídeo-Liases/genética , Polissacarídeo-Liases/química , Vibrio/enzimologia , Vibrio/genética , Alginatos/metabolismo , Alginatos/química , Ligação Proteica , Domínio Catalítico , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Solubilidade , Sequência de Aminoácidos , Temperatura , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética
2.
Langmuir ; 40(19): 10281-10292, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38687814

RESUMO

The flotation recovery of fine particles faces serious challenges due to the lack of kinetic energy required for supporting their radial displacement and attachment with bubbles. Generally, the hydrodynamic resistance and repulsive disjoining pressure successively inhibit the liquid outflow intervening between the bubble and solid surfaces. To quantitatively characterize the influence of the main repulsion on film thinning time, experiments have been designed in three different aqueous systems. Bubble surface mobility closely associated with hydrodynamic resistance was determined by the rising bubble technique, and the DLVO theory was employed to confirm the evolution of electrostatic repulsion. The film drainage process was then measured based on the high-speed microscopic interferometry. Furthermore, the influence of the main repulsion on bubble-solid surface interactions was examined by flotation recovery. Results show that the earlier buildup of hydrodynamic force ran through the whole film thinning process, and under immobile conditions, the central region gradually became dominant in film thinning due to the very limited fluid flow at the thinnest rim position. Therefore, to achieve the identical film thickness (∼100 nm), the large hydrodynamic resistance could prolong the film thinning time by about 1 order of magnitude, compared with that induced by electrostatic repulsion, which accounts for the increased flotation recovery by 10% using mobile bubbles. This study not only enhances the understanding of how typical repulsive forces work in film drainage dynamics but also opens up an avenue for enhancing flotation and avoiding wasting resources by modulating bubble surface mobility and thus micro/nanoscale fluid flow.

3.
Int Arch Allergy Immunol ; 185(7): 659-667, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38467118

RESUMO

INTRODUCTION: This study involves the collation and analysis of clinical characteristics and laboratory findings in patients with multiple myeloma (MM) combined with renal insufficiency. The objective was to assess the impact of various treatment methods on patient outcomes and the incidence of adverse events in individuals with MM and renal insufficiency. METHODS: We analyzed the correlation between clinical characteristics, gene loci, fluorescence in situ hybridization, treatment methods, and prognosis in patients with MM and renal insufficiency. The differences in hematological and therapeutic efficacy indexes between two groups subjected to different treatments were evaluated. The assessment of treatment effectiveness was based on the total effective rate, calculated as the sum of stringent CR rate, complete remission rate, very good partial remission rate, and partial remission rate. RESULTS: (1) The renal insufficiency group exhibited higher percentages of bone marrow abnormal plasma cells, lactate dehydrogenase (LDH), blood calcium, white blood cell count, percentage of neutrophils, and blood ß2-microglobulin (ß2-MG) levels compared to the normal renal function group. Conversely, hemoglobin levels and lymphocyte percentage were lower in the renal insufficiency group. Binary logistic regression analysis identified hemoglobin, blood calcium values, blood ß2-MG, and LDH as independent risk factors for the development of renal insufficiency in patients with MM (p < 0.05). (2) Based on the Durie-Salmon staging criteria, the proportion of Stage III patients was the highest (up to 81.8%), indicating that patients with MM usually suffer from insidious disease, often with high tumor load and late-disease stage at the time of consultation. International Staging System (ISS) and Revised ISS staging also revealed a higher proportion of Stage III patients in the renal insufficiency group (p < 0.05), indicating a worse long-term prognosis in patients with MM and renal insufficiency. (3) Before treatment, there was no significant difference between the two groups in the analysis of various indices. Complications such as sepsis, herpes zoster, peripheral neuropathy, thrombosis, secondary pulmonary infection, and cardiac complications were significantly lower in the BCD group (Bortezomib + Cyclophosphamide + Dexamethasone) compared to the BD group (Bortezomib + Dexamethasone) (χ2 = 6.333, p < 0.05), suggesting fewer complications with the BCD regimen. (4) The clinical treatment effects analysis indicated that the BCD group demonstrated a more significant impact than the BD group in the treatment of MM. CONCLUSION: The application of the BCD regimen in the treatment of MM has shown significant efficiency, effectively alleviating clinical symptoms with fewer adverse reactions and high safety.


Assuntos
Mieloma Múltiplo , Insuficiência Renal , Humanos , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/complicações , Mieloma Múltiplo/diagnóstico , Insuficiência Renal/etiologia , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Resultado do Tratamento , Prognóstico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Dexametasona/uso terapêutico , Adulto
4.
Math Biosci Eng ; 21(3): 3944-3966, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38549314

RESUMO

We proposed a novel decision-making method, the large-scale group consensus multi-attribute decision-making method based on probabilistic dual hesitant fuzzy sets, to address the challenge of large-scale group multi-attribute decision-making in fuzzy environments. This method concurrently accounted for the membership and non-membership degrees of decision-making experts in fuzzy environments and the corresponding probabilistic value to quantify expert decision information. Furthermore, it applied to complex scenarios involving groups of 20 or more decision-making experts. We delineated five major steps of the method, elaborating on the specific models and algorithms used in each phase. We began by constructing a probabilistic dual hesitant fuzzy information evaluation matrix and determining attribute weights. The following steps involved classifying large-scale decision-making expert groups and selecting the optimal classification scheme based on effectiveness assessment criteria. A global consensus degree threshold was established, followed by implementing a consensus-reaching model to synchronize opinions within the same class of expert groups. Decision information was integrated within and between classes using an information integration model, leading to a comprehensive decision matrix. Decision outcomes for the objects were then determined through a ranking method. The method's effectiveness and superiority were validated through a case study on urban emergency capability assessment, and its advantages were further emphasized in comparative analyses with other methods.

5.
Chemosphere ; 352: 141268, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38246499

RESUMO

Swimming consistency and respiration of fish are recognized as the non-invasive stress biomarkers. Their alterations could directly indicate the presence of pollutants in the water ecosystem. Since these biomarkers are a routine process for fish, it is difficult to monitor their activity manually. For this reason, experts employ engineering technologies to create sensors that can monitor the regular activities of fish. Knowing the importance of these non-invasive stress biomarkers, we developed online biological behavior monitoring system-OBBMS and online biological respiratory response monitoring system-OBRRMS to monitor real-time swimming consistency and respiratory response of fish, respectively. We continuously monitored the swimming consistency and respiration (OCR, CER and RQ) of zebrafish (control and atrazine-treatments) for 7 days using our homemade real-time biological response monitoring systems. Furthermore, we analyzed oxidative stress indicators (SOD, CAT and POD) within the vital tissues (gills, brain and muscle) of zebrafish during stipulated sampling periods. The differences in the swimming consistency and respiratory rate of zebrafish between the control and atrazine treatments could be precisely differentiated on the real-time datasets of OBBMS and OBRRMS. The zebrafish exposed to atrazine toxin showed a concentration-dependent effect (hypoactivity). The OCR and CER were increased in the atrazine treated zebrafish. Both Treatment I and II received a negative response for RQ. Atrazine toxicity let to a rise in the levels of SOD, CAT and POD in the vital tissues of zebrafish. The continuous acquisition of fish signals is achieved which is one of the main merits of our OBBMS and OBRRMS. Additionally, no special data processing was done, the real-time data sets were directly used on statistical tools and the differences between the factors (groups, photoperiods, exposure periods and their interactions) were identified precisely. Hence, our OBBMS and OBRRMS could be a promising tool for biological response-based real-time water quality monitoring studies.


Assuntos
Atrazina , Perciformes , Poluentes Químicos da Água , Animais , Antioxidantes , Peixe-Zebra/fisiologia , Natação , Atrazina/toxicidade , Qualidade da Água , Ecossistema , Respiração , Superóxido Dismutase , Biomarcadores , Poluentes Químicos da Água/toxicidade
6.
Langmuir ; 39(42): 14859-14868, 2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-37843017

RESUMO

Extended surfactants represent a novel class of anionic-nonionic surfactants with exceptional performance and unique application value in chemically enhanced oil recovery. Although molecular dynamics (MD) simulations can efficiently screen these surfactants, the current research is limited. Here, it is proven for the first time that existing generic force fields (GAFF and CHARMM) cannot accurately describe extended surfactants, and traditional approaches are insufficient for obtaining precise charge parameters. The concept of the respectively optimized force field (ROFF) with the purports of specialization and accuracy is proposed to construct high-accuracy models for MD simulations, and a new approach is developed to simulate the interface model. By combining the newly specialized alkane model, ROFF-based surfactant models, and the innovative simulation protocol, high accuracy and reliability can be obtained in predicting hydration free energies, minimum of area per molecule, and critical micelle concentration of extended surfactants. Key properties of the newly designed extended surfactants in conventional oil-water interfaces and oil reservoir environments are comprehensively predicted by using advanced analytical and characterization methods. Furthermore, the more rigorous mechanism underlying the special amphiphilicity of the extended surfactant is revealed, potentially offering significant improvements over previous empirical perspectives.

7.
Chemosphere ; 339: 139608, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37499804

RESUMO

Fe(II)-catalyzed PMS process was widely used in the degradation of refractory pollutants in wastewater, while its performance was restricted by the slow regeneration efficiency of Fe(II). Herein, caffeic acid (CFA), a representative of hydroxycinnamic acids, was introduced into Fe(III)/PMS system to accelerate the transformation of Fe(III) to Fe(II) and promote the removal of bisphenol A (BPA). Under optimum condition of 0.1 mM CFA, 0.05 mM Fe(III), and 0.5 mM PMS, almost complete removal of BPA can be achieved within 20 min, which was roughly 6.2 times higher than that in Fe(III)/PMS system. As the addition of CFA into Fe(III)/PMS system, pH application range was widened from acidic to alkaline conditions. The reduction and chelation of CFA expedited the Fe(III)/Fe(II) cycle by forming CFA-Fe chelate, thereby facilitating the PMS activation. Based on LC-MS analysis and DFT calculation, the intermediate products of CFA were found to play a decisive role in boosting the regeneration of Fe(II), and the toxicity of these intermediates towards organisms was evaluated by ECOSAR. The alcohol-scavenging and chemical probe tests certified that hydroxyl radical (•OH), sulfate radical (SO4•-), and Fe(IV) coexisted in Fe(III)/CFA/PMS system, and the second-order reaction rate constants of •OH and SO4•- reacted with CFA were calculated to be 3.16✕109 and 2.30✕1010 M-1 s-1, respectively. Two major degradation pathways of BPA, •OH addition and SO4•- induced hydroxylation reaction, were proposed. This work presented a novel green phenolic compound that expedited the Fe(II)-catalyzed PMS activation process for the treatment of organic contaminants.


Assuntos
Compostos Férricos , Poluentes Químicos da Água , Peróxidos/química , Poluentes Químicos da Água/análise , Oxirredução , Compostos Ferrosos
8.
Gene ; 867: 147346, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-36898514

RESUMO

Taraxacum kok-saghyz has been identified as one of the most promising alternative rubber crops, with laticifer cells that produce high-quality rubber. To uncover the underlying molecular mechanisms regulating natural rubber biosynthesis under MeJA induction, a reference transcriptome was constructed from nine samples of T. kok-saghyz. MeJA treatment was applied for 0 h (control), 6 h, and 24 h. A total of 7452 differentially expressed genes (DEGs) were identified in response to MeJA stress, relative to the control. Functional enrichment showed that these DEGs were primarily related to hormone signaling, defensive responses, and secondary metabolism. Combined analysis of the DEGs induced by MeJA and high-expression genes in laticifer cells further identified seven DEGs related to natural rubber biosynthesis that were upregulated in latex tissue, suggesting that these candidate genes could prove valuable in studying the mechanism of MeJA-mediated natural rubber biosynthesis. In addition, 415 MeJA-responsive DEGs were from several transcription factor families associated with drought resistance. This study helps to elucidate the mechanism of natural rubber biosynthesis in T. kok-saghyz in response to MeJA stress and identifies key candidate MeJA-induced DEGs in laticifer tissue, as well as a candidate drought-response target gene, whose knowledge will promote the breeding of T. kok-saghyz in the aspect of rubber yields and quality, and drought tolerance.


Assuntos
Borracha , Taraxacum , Borracha/metabolismo , Taraxacum/genética , Taraxacum/metabolismo , Resistência à Seca , Melhoramento Vegetal , Perfilação da Expressão Gênica , Transcriptoma , Regulação da Expressão Gênica de Plantas
9.
Artigo em Inglês | MEDLINE | ID: mdl-36901078

RESUMO

Green technologies are important for achieving green and high-quality agricultural development. The Chinese government has issued various policies to explicitly encourage the adoption of green technologies. However, incentives for Chinese farmers to adopt green technologies remain insufficient. This study examines whether participation in agricultural cooperatives can help break the barriers to Chinese farmers' adoption of green technologies. It also examines the potential mechanisms by which cooperatives can mitigate the lack of incentives for farmers to adopt agricultural green technologies. Using data from a study on farmers in four Chinese provinces, we found that cooperative participation significantly increases farmers' adoption behavior for both green technologies with effective market incentives (e.g., commercial organic fertilizer technologies) and those without such incentives (e.g., water-saving irrigation technologies).


Assuntos
Agricultura , Fazendeiros , Humanos , Tecnologia , Motivação , Fertilizantes , China
10.
J Environ Sci (China) ; 129: 104-114, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36804227

RESUMO

Thallium contamination in water can cause great danger to the environment. In this study, we synthesized manganese oxide-coated sand (MOCS) and investigated the transport and retention behaviors of Tl(I) in MOCS under different conditions. Characterization methods combined with a two-site nonequilibrium transport model were applied to explore the retention mechanisms. The results showed that Tl(I) mobility was strongly inhibited in MOCS media, and the retention capacity calculated from the fitted model was 510.41 mg/g under neutral conditions. The retention process included adsorption and oxidative precipitation by the manganese oxides coated on the sand surface. Cotransport with the same concentration of Mn(II) led to halving Tl(I) retention due to competition for reactive sites. Enhanced Tl(I) retention was observed under alkaline conditions, as increasing pH promoted electronegativity on the media surface. Moreover, the competitive cation Ca2+ significantly weakened Tl(I) retention by occupying adsorption sites. These findings provide new insights into understanding Tl(I) transport behavior in water-saturated porous media and suggest that manganese oxide-coated sand can be a cost-effective filter media for treating Tl-contaminated water.


Assuntos
Areia , Tálio , Tálio/análise , Óxidos/química , Água , Adsorção , Dióxido de Silício/química
11.
Plants (Basel) ; 12(2)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36678964

RESUMO

Taraxacum kok-saghyz is a model species for studying natural rubber biosynthesis because its root can produce high-quality rubber. Small rubber particle protein (SRPP), a stress-related gene to multiple stress responses, involves in natural rubber biosynthesis. To investigate the transcriptional regulation of the TkSRPP promoter, the full-length promoter PR0 (2188 bp) and its four deletion derivatives, PR1 (1592 bp), PR2 (1274 bp), PR3 (934 bp), and PR4 (450 bp), were fused to ß-glucuronidase (GUS) reporter gene and transformed into tobacco. The GUS tissue staining showed that the five promoters distinctly regulated GUS expression utilizing transient transformation of tobacco. The GUS activity driven by a PR0 promoter was detected in transgenic tobacco leaves, stem and roots, suggesting that the TkSRPP promoter was not tissue-specific. Deletion analyses in transgenic tobacco have demonstrated that the PR3 from -934 bp to -450 bp core region responded strongly to the hormones, methyl jasmonate (MeJA), abscisic acid (ABA), and salicylic acid (SA), and also to injury induction. The TkSRPP gene was highly expressed under hormones and wound-induced conditions. This study reveals the regulation pattern of the SRPP promoter, and provides valuable information for studying natural rubber biosynthesis under hormones and wounding stress.

12.
Phys Chem Chem Phys ; 25(1): 366-374, 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36477340

RESUMO

Three accurate global adiabatic potential energy surfaces for the 13A'', 13A' and 21A' states of SiH2 are constructed by fitting numerous ab initio energies calculated at the aug-cc-pV(Q+d)Z and aug-cc-pV(5+d)Z basis sets based on the multi-reference configuration interaction level with Davidson correction. It is worth noting that the potential energy surface of the 13A'' state is established for the first time. The topographic features of these novel potential energy surfaces are investigated in detail and are very consistent with those obtained in the available literature. Moreover, the integral cross-sections of the corresponding reaction are calculated for the first time using a quasi-classical trajectory method and time-dependent wave packet method, indicating that the 13A'' state makes a major contribution to the reaction of Si(3P) + H2(X1Σ+g) (v = 0, j = 0) → H(2S) + SiH(X2Π) at high collision energies. These new potential energy surfaces provide a reliable foundation for investigation of the dynamics and a component for constructing larger silicon-/hydrogen-containing systems.

13.
Environ Res ; 215(Pt 3): 114333, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36167109

RESUMO

Geopolymer is always regarded as a promising material for the immobilization of radioactive waste. In the present study, the stabilization of Cs in geopolymers activated by NaOH and Na2SiO3 solutions and calcined at various temperatures was studied via toxicity characteristic leaching procedure (TCLP), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope and energy dispersive spectroscopy (SEM-EDS), solid-state nuclear magnetic resonance (SSNMR), and N2 adsorption-desorption isotherm. For both NaOH-activated and Na2SiO3-activated geopolymers, the leaching concentrations of Cs decreased with the increase of calcination temperature. Specifically, most of the amorphous substance was crystallized to nepheline at 1000 °C for NaOH-activated geopolymer, and Cs+ can be incorporated into the structure of nepheline, contributing to the reduction of Cs leaching concentration. However, the amorphous structure was still maintained for Na2SiO3-activated geopolymer even after calcination at 1000 °C. It has been deduced that the main structure of Na2SiO3-activated geopolymer after calcination at 1000 °C should be in short-range order and Cs+ can be locked in a micro "crystal" structure. In addition, the change of specific surface area was not fully consistent with the decreasing trend of Cs leaching concentration. Therefore, the inner structure and the specific surface area of geopolymer should have a combined effect on the leaching behavior of Cs. This study can provide new insights into the application of geopolymer to immobilize radionuclides.


Assuntos
Resíduos Radioativos , Compostos de Alumínio , Césio , Silicatos , Compostos de Sódio , Hidróxido de Sódio/química , Temperatura
14.
ACS Omega ; 7(31): 27542-27549, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35967042

RESUMO

The mass production of flotation tailings has become a serious risk to the environment. Re-concentration of tailings is one of the best ways to solve this problem, which requires a better understanding of flotation tailings. In the present work, flotation kinetics, timed-release flotation, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and solid-state nuclear magnetic resonance (SSNMR) were used to analyze the properties of flotation tailings with different particle sizes and densities, the occurrence and binding state of gangue minerals in tailing, and the transportation behaviors in the re-flotation process. Flotation results showed that the flotation yield exhibited little change with the extension of flotation time, while the ash content of the froth concentrates increased. An increase of the flotation time could reduce the ash content of the obtained product. The characterization results confirmed that the main gangue minerals in the tailings were kaolinite and quartz. With the decrease of particle size or the increase of floating and sinking density, the contents of kaolinite and quartz increased. However, due to the different dissemination characteristics of kaolinite and quartz in the tailings, the distributions of kaolinite and quartz in the different particle sizes and densities of tailing had differences. Although both kaolinite and quartz could exist as monomers, kaolinite was more easily associated with coal. Based on the above cognition, a new flotation method is proposed for coal flotation tailing. A part of the concentrates in the early stage of flotation should be scraped out quickly. Then, the concentrates obtained in the later stage of flotation are collected and merged into the concentrates obtained during the early stage of flotation, while the secondary tailing is directly pumped into the raw feed system.

15.
Water Res ; 221: 118836, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35839593

RESUMO

The reversibility of monovalent thallium (Tl) absorption on widely distributed iron/manganese secondary minerals may affect environmental Tl migration and global cycling. Nevertheless, quantitative and mechanistic studies on the interfacial retention and release reactions involving Tl(I) are limited. In this study, batch and stirred-flow experiments, unified kinetics modeling, spectral detection, and theoretical calculations were used to elucidate the retention behaviors of Tl(I) on goethite, hematite, and manganite with different solution pH values and Tl loading concentrations. Sustained Tl(I) retention (kd, MeOHTl=0.005∼0.018 min-1) was induced by hydration of the surface hydroxyl groups. Rapid Tl(I) retention (kd,MeOTlOH=1.232∼2.917 min-1) was enhanced by the abundant hydroxide ions and deprotonated hydroxyl groups, which increased the Tl(I) binding ability. Compared to the ambient Tl concentration, pH had a more substantial effect on the formation and distribution of surface Tl(I) binding species. In alkaline environments, the large adsorption energy for Tl(I) binding to surface species (Eads=-6.14 eV) induced fast Tl(I) binding response on the surfaces of iron/manganese secondary minerals. This study provides new insights into the heterogeneous surface complexation and retention behaviors of Tl(I) and contributes to an in-depth understanding of the environmental fate of Tl and the remediation of Tl contamination.


Assuntos
Manganês , Tálio , Adsorção , Compostos Férricos , Ferro , Compostos de Ferro , Compostos de Manganês , Minerais
16.
Phys Chem Chem Phys ; 24(27): 16637-16646, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35766326

RESUMO

An accurate potential energy surface is constructed for the excited state of AlH2 by fitting extensive ab initio points calculated at the multi-reference configuration interaction level based on aug-cc-pV(Q+d)Z and aug-cc-pV(5+d)Z basis sets. All the calculated energies are corrected via the many-body expansion method and extrapolated to the complete basis set limit. The various topographic features of the new potential energy surface are investigated to demonstrate the correct behavior of Al(3P) + H2(X1Σg+) and AlH(a3Π) + H(2S) dissociation limits. By employing the time-dependent wave packet approach, the integral scattering cross-sections obtained from the Coriolis coupling calculation and the centrifugal sudden approximation, respectively, are compared in detail and show that the former has a higher effect on the reaction. Moreover, the thermal rate constants for Al(3P) + H2 (v0 = 0-3, j0 = 0, 2, 4, 6) in the temperature range of 0-5000 K are calculated, thereby providing insights into the influence of ro-vibrational quantum numbers on the thermal rate constants.

17.
Phys Chem Chem Phys ; 24(13): 7759-7767, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35293900

RESUMO

An accurate many-body expansion potential energy surface for the ground state of SiH2 is reported. To warrant the correct behavior at the Si (1D) + H2 (X1Σ+g) dissociation channels involving silicon in the first excited Si (1D) and ground Si (3P) states, a switching function formalism has been utilized. A great deal of ab initio points based on aug-cc-pV(Q+d)Z and aug-cc-pV(5+d)Z basis sets are utilized at the multi-reference configuration interaction level using the full-valence-complete-active-space wave function as the reference. Subsequently the calculated energies are corrected via a many-body expansion method to extrapolate to the complete basis set limit. The topographic features of the novel many-body expansion global potential energy surface are studied in detail, showing a good agreement with the theoretical and experimental results in the literature. Moreover, the integral cross-section of the Si (1D) + H2 (X1Σ+g) → H (2S) + SiH (X2Π) reaction has been calculated using the time-dependent wave packet method, which provides support for the reliability of the title potential energy surface. This work can serve as the foundation for the study of Si (1D) + H2 (X1Σ+g) reaction kinetics, and for the construction of the larger multibody expansion potential energy surface of silicon/hydrogen containing systems.

18.
J Hazard Mater ; 428: 128230, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35030487

RESUMO

The transformations of monovalent thallium (Tl) in an aqueous environment may be affected significantly by Tl(I) partitioning at the solid-water interface during sorption. Models used to quantify the kinetics of Tl(I) adsorption on heterogeneous adsorbents and formation of multiple complexes under a wide range of water chemistry conditions can accurately predict the environmental fate of thallium. In this study, Tl(I) sorption on representative titanium dioxide at different solution pH values and loading concentrations was investigated with two unified adsorption models, diffuse layer modeling and kinetics modeling. Three Tl(I) surface complexes, TiOTl, TiOHTl+, and TiOTlOH-, were used in the diffuse layer model and successfully described batch adsorption and the results of spectroscopic analyses. The contribution of TiOHTl+ to the adsorption capacity was much higher than those of TiOTl and TiOTlOH- under neutral and weakly alkaline conditions, while the species TiOTlOH- predominated among Tl(I) complexes in strongly alkaline environments. The adsorption and desorption rate coefficients derived from thermodynamics and kinetics coupling modeling suggested the influence of different complex characteristics on adsorption and desorption of Tl(I). Our results provide a comprehensive model for predicting the dynamic binding behavior of Tl at heterogeneous solid-water interfaces.

19.
J Phys Chem A ; 126(1): 53-60, 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-34965124

RESUMO

A great number of ab initio energy points are calculated using the aug-cc-pV(Q,5)Z basis sets at the multireference configuration interaction level and extrapolated to the complete basis set limit. An exact three-dimensional potential energy surface of the ground-state BH2+ is obtained. A switching function is developed to model the transition of B+(3P) to B+(1S) to guarantee the reliable behavior at B+(3P) + H2(X1∑g+) and BH+(X2∑+) + H(2S) dissociation limits. The various topographic features of the new global potential energy surface are discussed in detail, showing a good agreement with the previous results from the theory. The quasi-classical trajectory method is utilized to calculate the integral cross sections of the B+(3P) + H2(X1∑g+) (v = 0, j = 0) → BH+(X2∑+) + H(2S) reaction, which can provide another support for reliability of the title potential energy surface.

20.
J Hazard Mater ; 422: 126910, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416700

RESUMO

Exploring the transport behaviors of thallium (Tl) in porous media is crucial for predicting Tl pollution in natural soils and groundwater. In recent years, the misuse of plastics has led to plastic becoming an emerging pollutant in soil. In this work, the effects of plastic particles on Tl(I) transport in water-saturated sand columns were investigated under different ionic strengths (ISs), pH values, and plastic particle sizes. The two-site nonequilibrium model was selected to fit the breakthrough curves (BTCs) of Tl(I). The results demonstrated that nanoplastics (NPs) accelerated Tl(I) transport at pH 7, which might be attributed to the competitive adsorption of NPs and Tl(I) on sand surfaces. However, at pH 5, the deposited NPs might provide more adsorption sites for Tl(I), and thus enhance its retention in the columns. In addition, the "straining" process could intercept microplastics (MPs) with Tl(I) that was attached under unfavorable attachment conditions, which would result in the inhibited mobility of Tl(I). On the other hand, the migration of plastics was restrained to some extent when Tl(I) was present. Overall, the findings from this work provided a new perspective for understanding the transport of Tl(I) and plastics in subsurface environments.

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