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1.
J Colloid Interface Sci ; 606(Pt 2): 1662-1672, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34507166

RESUMO

Efficient and durable non-precious catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is pivotal for practical water electrolysis toward clean hydrogen fuel. Herein, a molybdenum oxide-FeCoCu alloy hybrid (MoOx-FeCoCu) catalyst was designed by polyoxometallate (POM) molecular cluster mediated solvothermal alcoholysis and ammonolysis of metal salts followed by pyrolytic reduction treatment. The HER efficiency is substantially enhanced by the ternary alloy component, which is more close to the benchmark Pt/C catalyst, and the HER catalytic stability is also superior to Pt/C catalyst. Moreover, the MoOx-FeCoCu demonstrates high catalytic efficiency and rather good durability for OER. Benefitted by the bifunctional catalytic behaviors for HER and OER, the symmetric water electrolyzer based on the MoOx-FeCoCu electrode requires a low driving voltage of 1.69 V to deliver a response current density of 10 mA cm-2, which is comparable to that based on the benchmark Pt/C HER cathode and RuO2 OER anode. The current work offers a feasible way to design efficient bifunctional catalyst for water electrolysis via POM mediated co-assembly and calcination treatment.

2.
Artigo em Inglês | MEDLINE | ID: mdl-34807560

RESUMO

A promising magnetocaloric effect has been obtained in Ni-(Co)-Mn-X (X = Sn, In, Sb)-based Heusler alloys, but the low isothermal magnetic entropy change ΔSM restricts the further promotion of such materials. Defect engineering is a useful method to modulate magnetic performance and shows great potential in improving the magnetocaloric effect. In this work, dense Ni vacancies are introduced in Ni41Mn43Co6Sn10 alloys by employing high-energy electron irradiation to adjust the magnetic properties. These vacancies bring about intense lattice distortion to change the distance between adjacent magnetic atoms, leading to a significant enhancement of the average magnetic moment. As a result, the saturation magnetization of ferromagnetic austenite is accordingly improved to generate a high isothermal magnetic entropy change ΔSM of 20.0 J/(kg K) at a very low magnetic field of ∼2 T.

3.
Small ; : e2104524, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34816615

RESUMO

Structural modulation of core-shell silver nanoclusters from the inside is a huge challenge but of great importance in their syntheses. Herein, two silver nanoclusters [Ag3 S9 @Ag42 ] (SD/Ag45b) and [Ag9 S9 @Ag42 ] (SD/Ag51a) are isolated in the presence of different kinds of sulfonic acids. Uniquely, SD/Ag45b and SD/Ag51a show typical core-shell structures with the similar Ag42 shell but different cores. The outer shell of 42 silver atoms comprises two Ag3 trigons at two poles encircled by three equatorial distorted square cupolas (J4 , Ag12 ). The core in SD/Ag45b is a silver trigon ligated by nine S2- ions (Ag3 S9 ), while a tricapped triangular prismatic Ag9 also ligated by the same amount of S2- ions (Ag9 S9 ) is observed in the inner core of SD/Ag51a. The electrospray ionization mass spectrometry (ESI-MS) indicates that the introduction of p-toluenesulfonic acid can realize the transformation from SD/Ag45b to Ag51 . SD/Ag45b and SD/Ag51a show inverse luminescence thermochromic behaviors in the near-infrared (NIR) region, mainly dictated by the inner silver cores. This work not only realizes the synthesis of new silver nanoclusters by core modulation but also provides a prototype to get molecular-level insight into the correlation between structure and luminescence thermochromism.

4.
Pathogens ; 10(11)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34832539

RESUMO

Human norovirus (HuNoV) is a food-borne pathogen that causes acute gastroenteritis in people of all ages worldwide. However, no approved vaccines and antiviral drugs are available at present. Therefore, the development of accurate and rapid detection technologies is important in controlling the outbreak of HuNoVs. This paper reviewed the research progress on HuNoV detection, including immunological methods, molecular detection and biosensor technology. Immunological methods and molecular detection technologies are still widely used for HuNoV detection. Furthermore, biosensors will become an emerging developmental direction for the rapid detection of HuNoVs because of their high sensitivity, low cost, easy operation and suitability for onsite detection.

5.
China CDC Wkly ; 3(33): 702-705, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34594972

RESUMO

What is already known on this topic?: The norovirus has often caused outbreaks in schools and kindergartens, but minimal research has been performed on environmental contamination during norovirus outbreaks in schools and kindergartens. What is added by this report?: This report conveys the norovirus detection rates and viral loads in different environmental sites in 45 norovirus outbreaks in Beijing Municipality from October to December 2020. What are the implications for public health practice?: The evidence presented here can instruct professionals and the public to sample and disinfect key locations of the environment purposefully when responding to norovirus outbreaks.

6.
Biochem Biophys Res Commun ; 583: 1-6, 2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34715495

RESUMO

Ubiquitination is a pivotal post-translational modification that regulates turnover of nucleotide-binding site and leucine-rich repeat receptors (NLRs). As a RING-type E3 ligase, BOI (Botrytis susceptible1 interactor) has been reported to interact with different proteins, and function in the nucleus. New studies have identified that BOI can interact and ubiquitinate L5 (AT1G12290), a CC-NBS-LRR protein in vitro, and mediate the proteasomal degradation of L5 in Nicotiana benthamiana and Arabidopsis thaliana. However, there still remains an unanswered question about where the degradation occurs at the subcellular level. In this study, the ubiquitination of L5 by BOI was determined in N. benthamiana. Meanwhile, we discovered that BOI exhibited nucleocytoplasmic localization and mediated the degradation of the plasma membrane localized L5 outside the nucleus. BOI and its homologs BRG1 and BRG3 function redundantly in negatively regulate the protein level of L5. Overall, this report reveals BOI and its homologs have multiple targets and function at different subcellular locations.

7.
Inorg Chem ; 60(19): 14866-14871, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34533931

RESUMO

The mild reaction of the preorganized silsesquioxane precursor with Mn(II) acetate under ambient conditions results in a mixed-valent {MnII6MnIII4} nanocage (SD/Mn10) which is protected by both acyclic trimer [Si3] and cyclic tetramer [Si4]. Serendipitous capture of atmospheric CO2 as a µ5-carbonate anion placed at the center supports the formation of the cluster. The magnetic analysis reveals the strong antiferromagnetic interactions between Mn ions. Moreover, the drop-casting film of SD/Mn10 shows photoelectric activity indicating its great potential as a semiconductor for photoelectric conversion applications.

8.
Biochem Biophys Res Commun ; 578: 104-109, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34560579

RESUMO

Nucleotide-binding site and leucine-rich repeat receptors (NLRs) play pivotal roles in plant immunity. The regulation of NLR stability is essential to ensure effective immunity, whereas the exact mechanism is largely unclear. The Arabidopsis CC-NBS-LRR protein L5 (At1g12290) can induce cell death in Nicotiana benthamiana, but not in Arabidopsis thaliana. We screened the interactors of L5 by yeast two-hybrid, and found that the BOI can interact with the CC domain of L5. Transiently expressed BOI reduced the protein level of L5, and suppressed the auoactivity of L5 in N. benthamiana. BOI can interact and ubiquitinate L5 in vitro, and mediate the proteasomal degradation of L5 in N. benthamiana and Arabidopsis. The Lys425 in the NBS domain of L5 is the critical unbiquitin site for the degradation. In conclusion, our results reveal a mechanism for the control of the stability of L5 protein and for the suppressed of L5-triggered cell death by a RING-type E3 ligase through the ubiquitin proteasome system.

9.
ACS Nano ; 15(10): 16019-16029, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34592104

RESUMO

Controllable syntheses of Au nanoclusters (NCs) with different nuclearities are of great significance due to the kernel-dependent physicochemical properties. Herein, two pairs of enantiomeric Au NCs [Au19(R/S-BINAP)4(PhC≡C)Cl4] (SD/Au19) and [Au11(R/S-BINAP)4(PhC≡C)2]·Cl (SD/Au11), both with atropos (rigid axial chirality) diphosphine BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthalene) as the predominant organic ligands, were controllably synthesized through precursor engineering. The former was obtained by direct reduction of HAuCl4·4H2O, while the latter was obtained by reduction of [Au(SMe2)Cl] instead. Intriguingly, the kernel of SD/Au19 contains an Au7 pentagonal bipyramid capped by two boat-like Au6 rings, which represents another type of Au19 kernel, making SD/Au19 a good candidate for comparative study with other Au19 NCs to get more insight into the distinct structural evolution of phosphine-protected Au NCs. Despite the previous chiroptical studies on some other chiral undecagold NCs, the successful attainment of the X-ray crystal structures for SD/Au11 not only provides a step forward toward better correlating the chiroptical activities with their structural details but also reveals that even the auxiliary protecting ligands also play a nontrivial role in tuning the geometrical structures of the metal NCs. The chiroptical activities of both SD/Au19 and SD/Au11 were found to originate from the chiral ligands and core distortions; the extended π-electron systems in the BINAP ligands have proved to positively contribute to the electronic absorptions and thus disturb the corresponding circular dichroism (CD) responses.

10.
Nat Commun ; 12(1): 4966, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404784

RESUMO

Although chirality is an ever-present characteristic in biology and some artificial molecules, controlling the chirality and demystifying the chirality origin of complex assemblies remain challenging. Herein, we report two homochiral Ag14 nanoclusters with inherent chirality originated from identical rotation of six square faces on a Ag8 cube driven by intra-cluster π···π stacking interaction between pntp- (Hpntp = p-nitrothiophenol) ligands. The spontaneous resolution of the racemic (SD/rac-Ag14a) to homochiral nanoclusters (SD/L-Ag14 and SD/R-Ag14) can be realized by re-crystallizing SD/rac-Ag14a in acetonitrile, which promotes the homochiral crystallization in solid state by forming C-H···O/N hydrogen bonds with nitro oxygen atoms in pntp- or aromatic hydrogen atoms in dpph (dpph = 1,6-bis(diphenylphosphino)hexane) on Ag14 nanocluster. This work not only provides strategic guidance for the syntheses of chiral silver nanoclusters in an all-achiral environment, but also deciphers the origin of chirality at molecular level by identifying the special effects of intra- and inter-cluster supramolecular interactions.


Assuntos
Cristalização , Compostos Organometálicos/química , Fenômenos Físicos , Prata/química , Acetonitrilas/química , Cristalografia por Raios X , Hexanos , Hidrogênio , Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Oxigênio , Rotação
11.
Chem Biol Interact ; 346: 109570, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34217686

RESUMO

Verapamil is reported to prevent scar formation. However, whether verapamil is involved in the ureteral stricture scar and the underlying mechanism need further investigation. Fibroblasts were isolated from ureteral scar tissues. TGF-ß1 stimulation was used to induce fibrosis of fibroblasts. Inhibition of CaMK II was achieved by shRNA transfection. CCK-8 was performed to evaluate cell viability. qRT-PCR was applied to determine the level of mRNA while western blotting was used to determine the level of proteins. Immunofluorescence was used to detect the level of vimentin, collagen I and collagen III. Primary fibroblasts was successfully isolated from ureteral scar tissues. TGF-ß1 stimulation was capable to induce collagen production and fibrosis in primary fibroblasts while inhibition of CaMK II attenuate collagen production. Overexpression of wild type CaMK II lead to further increase of collagen production upon TGF-ß1 stimulation while the mutated CaMK II did not exert this promotion. Treatment of verapamil inhibits TGF-ß1 induced collagen production via inhibiting CaMK II. In present study, we revealed a vital role of Verapamil and CaMK II in the formation of ureteral scar. Verapamil inhibited TGF-ß1 induced collagen fiber formation by regulating CaMK II. Our finding might provide new insight into mechanism of prevention and treatment of ureteral scar.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismo , Verapamil/farmacologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Células Cultivadas , Cicatriz/tratamento farmacológico , Cicatriz/metabolismo , Cicatriz/patologia , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Mutagênese , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Fator de Crescimento Transformador beta1/farmacologia , Regulação para Cima/efeitos dos fármacos , Verapamil/uso terapêutico , Vimentina/metabolismo
12.
Genes (Basel) ; 12(5)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064770

RESUMO

Lodging reduces rice yield, but increasing lodging resistance (LR) usually limits yield potential. Stem strength and leaf type are major traits related to LR and yield, respectively. Hence, understanding the genetic basis of stem strength and leaf type is of help to reduce lodging and increase yield in LR breeding. Here, we carried out an association analysis to identify quantitative trait locus (QTLs) affecting stem strength-related traits (internode length/IL, stem wall thickness/SWT, stem outer diameter/SOD, and stem inner diameter/SID) and leaf type-associated traits (Flag leaf length/FLL, Flag leaf angle/FLA, Flag leaf width/FLW, leaf-rolling/LFR and SPAD/Soil, and plant analyzer development) using a diverse panel of 550 accessions and evaluated over two years. Genome-wide association study (GWAS) using 4,076,837 high-quality single-nucleotide polymorphisms (SNPs) identified 89 QTLs for the nine traits. Next, through "gene-based association analysis, haplotype analysis, and functional annotation", the scope was narrowed down step by step. Finally, we identified 21 candidate genes in 9 important QTLs that included four reported genes (TUT1, OsCCC1, CFL1, and ACL-D), and seventeen novel candidate genes. Introgression of alleles, which are beneficial for both stem strength and leaf type, or pyramiding stem strength alleles and leaf type alleles, can be employed for LR breeding. All in all, the experimental data and the identified candidate genes in this study provide a useful reference for the genetic improvement of rice LR.


Assuntos
Oryza/genética , Caules de Planta/genética , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável , Oryza/fisiologia , Locos de Características Quantitativas
13.
J Med Virol ; 93(11): 6191-6199, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34028862

RESUMO

Group A rotavirus (RVA) is one of the most common causes of severe diarrhea in children worldwide. However, RVA is also an important pathogen causing adult diarrhea, with higher infection rates in older patients. To provide evidence for rotavirus epidemic control and to inform vaccine development, we analyzed the molecular epidemiology of RVA among adult outpatients with diarrhea in Beijing from 2011 to 2018. Stool specimens were collected monthly from 14 districts. RVA was detected using enzyme-linked immunosorbent assay and real-time reverse-transcription polymerase chain reaction (RT-PCR). Genotyping of rotavirus was performed using multiplex semi-nested RT-PCR. Phylogenetic analysis was performed using maximum likelihood methods implemented in MEGA software (version 6.06). Logistic regression and chi-square tests were used to assess differences among age groups, districts, years, and genotype distributions. The prevalence of rotavirus was 10.16% (1310 of 12,893) among adult outpatients with diarrhea from 2011 to 2018 in Beijing. The highest prevalence (13.74%, 600 of 4367) was observed among those aged 41 to 65 years. November, December, and January had the highest positive detection rates. In 2011, G3P[8] and G9P[8] were the dominant genotypes. Starting from 2012, G9P[8] became the dominant genotype. Most G9 strains belonged to the G9-VI clade. Most P[8] strains belonged to the P[8]-III clade. RVA is a major cause of adult diarrhea in Beijing. Continuous molecular surveillance is needed, and transmission of rotavirus between children and adults should be investigated further.

14.
Biochem Biophys Res Commun ; 555: 40-45, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-33812057

RESUMO

RIN4 is an important immunomodulator in Arabidopsis, which is targeted by multiple pathogenic effectors, and consequently guarded by different immune receptors. Although RIN4 plays a significant role in plant immunity, its molecular function is not fully understood. We found that RIN4 interacts with the exocyst subunit EXO70E2. Transiently expressed RIN4 can recruits EXO70E2 vesicles to the plasma membrane, and promote the transport of the vesicles to the extracellular matrix. RIN4 also can decrease the protein level of EXO70E2. Base on the fact that EXO70 proteins positively mediates plant immunity, the function of RIN4 is to promote the extracellular export of defense related vesicles. Pathogens will secret effectors to modify or cleavage it to interfere this exocytosis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Membrana Celular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Imunidade Vegetal , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , Transporte Proteico , Tabaco/genética , Proteínas de Transporte Vesicular/genética
15.
Cancer Manag Res ; 13: 2701-2715, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790645

RESUMO

Background: Recent studies showed circular RNAs (circRNAs) played regulatory roles in bladder cancer (BC). However, the relevance of circ_0000629, a newly identified circRNA, has not been determined yet. We aimed to characterize the function of circ_0000629 in BC and the relevant mechanism. Methods: First, we downloaded circRNA-related microarrays GSE147985 and GSE92675 from the GEO database, followed by a validation in our clinically obtained samples. We then overexpressed circ_0000629 in T24 and SW780 cells and evaluated the effects of circ_0000629 on BC cell proliferatory, apoptotic, and metastatic abilities. We further detected the subcellular localization of circ_0000629 in T24 and SW780 cells by the fractionation and export assay and FISH experiments. Integrated microarray analyses and bioinformatics website prediction were utilized to screen out the downstream microRNA (miRNA)/mRNA. The effects of miR-1290 and CDC73 on BC cell growth and metastasis was verified by functional rescue experiments. In addition, mice xenografts were built to measure the effect of circ_0000629 on tumor growth in vivo. Results: Circ_0000629 and CDC73 were reduced, and miR-1290 was significantly overexpressed in BC tissues and cells. Moreover, circ_0000629 significantly inhibited the development and metastasis of BC cells, but further overexpression of miR-1290 or knockdown of CDC73 attenuated the inhibitory effect of circ_0000629 on BC cells. Circ_0000629 localized in the cytoplasm and regulated CDC73 expression by sponging miR-1290. Further, overexpressed circ_0000629 reduced the BC tumor growth in vivo. Conclusion: Circ_0000629 promotes the expression of CDC73 by competitively binding to miR-1290, thereby inhibiting the growth and metastasis of BC cells.

16.
ACS Nano ; 15(5): 8733-8741, 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-33909407

RESUMO

Precision loading of nanoclusters in confined spaces, which has been enthusiastically pursued in the scientific realm, is still associated with some mysteries of "how", "when", and "why". Here, we isolated two similar heterometallic cluster-in-cage compounds, [Ag@Cu12S8@Cu4(dpph)6]X (X = OH, SD/AgCu16a and X = PF6, SD/AgCu16b; SD = SunDi), by use of an antigalvanic reaction between organometallic [PhC≡CCu]n and Ph3CSH with elemental silver. Both compounds are formed by fitting an Archimedean Ag@Cu12 cuboctahedral cluster into a Platonic Cu4(dpph)6 tetrahedral cage [dpph = bis(diphenylphosphino)hexane]. The Ag@Cu12 cluster is a hollow cuboctahedral Cu12 cage filled with a central AgI atom, and all eight triangular faces of the Ag@Cu12 cuboctahedron are triply capped by eight S2- ions, four of which in a tetrahedral array further internally pillar four Cu vertices of the outer Cu4(dpph)6 tetrahedron, fixing the cluster in the cage. Both compounds can be deemed as molecular fragments excised from porous nanomaterials filled with discrete nanoclusters, thus providing more details for understanding the confined growth of atomically precise nanoclusters. Electrospray ionization mass spectrometry (ESI-MS) reveals that the AgCu16 cluster is quite stable in CH2Cl2 and can stepwise lose dpph ligand in the gas phase under increased collision energy. This work not only presents a precise aggregation of metal atoms in a confined cavity to form a cluster-in-cage compound but also provides deep insights into the binding and geometry matching between clusters and cages in one entity.

17.
Dalton Trans ; 50(12): 4355-4362, 2021 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-33690776

RESUMO

Three novel cicada-like nickel(ii) clusters, formulated as [Ni6(bdped)2(mba)6(Hdmpz)2(NO3)2(H2O)2]·4MeCN (SD/Ni6b), [Ni5(bdped)2(tca)6(Hdmpz)(MeOH)2(H2O)]·MeOH (SD/Ni5a) and [Ni4(Hbdped)2(ba)4(Hdmpz)2]·2NO3·2MeCN (SD/Ni4a), were obtained by tuning the auxiliary carboxylic acids, where H2bdped = 1,2-bis-(3,5-dimethylpyrazol-1-yl)-ethane-1,2-diol; Hmba = 2-methylbenzoic acid; Hdmpz = 3,5-dimethyl-1H-pyrazole; Htca = 3-thiophenecarboxylic acid; and Hba = benzoic acid. The structures of SD/Ni6b, SD/Ni5a and SD/Ni4a are built from a central Ni4O4 opened cube, appending two to zero NiNO5 octahedra. The solution behaviours of SD/Ni6b, SD/Ni5a and SD/Ni4a were studied in detail via an ESI-MS technique and their solution stabilities were confirmed. Magnetic analysis indicated the presence of Ising-type anisotropy: D = -13, -10, and -11 cm-1 for SD/Ni6b, SD/Ni5a, and SD/Ni4a, respectively; moreover, dominantly ferromagnetic interactions were found between magnetic centers: J1 = 6.5 cm-1, J2 = -0.44 cm-1 and J1 = 5.9 cm-1, J2 = 2.6 cm-1 for SD/Ni5a and SD/Ni4a, respectively. Besides, the photocurrent signals were observed and they reached the maximum very quickly for these three nickel(ii) clusters and then their current intensities remained almost constant, which provide a possibility to be used for light-harvesting and photo-related catalysis.

18.
Adv Colloid Interface Sci ; 290: 102382, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33676242

RESUMO

Fluorite, as a scarce nonrenewable strategic non-metallic mineral resource, is the primary raw material for fluorine products used in diverse fields such as metallurgy, national defense, chemical and optical industries. With the increasing expansion of the related fields, the demand for high-quality fluorite continues to grow. Hence, the surge of interest in effectively utilizing fluorite resources has led to vast attention worldwide. So far, significant endeavors have been done to enhance the beneficiation of fluorite from relatively low-grade ores. It has been well appreciated that the froth flotation is of the most importance. However, to the best of the authors' knowledge, it lacks a thorough and critical review on the recent developments in fluorite flotation. This article begins with introducing the deposits and unique physical and chemical properties of fluorite from the perspective of the crystal structure. It is followed by a systematic review of common reagents involved in fluorite flotation, including collectors, depressants, regulators, modifiers, and frothers. Specifically, the synergistic effect of collectors and depressants on the recovery of fluorite is elaborated for the first time. Finally, the most widely seen fluorite-flotation cases, including separation of fluorite from quartz, calcite, barite, and sulfide, are summarized individually. The present review sheds new light on the deep understanding of fluorite flotation, the future synthesis of reagents, as well as their schemes in practical use. Meanwhile, such a novel rain of thought provided in this work has the potential to guide the flotation of other similar minerals extensively.

19.
Langmuir ; 37(11): 3490-3499, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33709716

RESUMO

Surface coordination chemistry is important in areas such as adsorption, separation, and catalysts. In this work, surface coordination interactions of benzohydroxamic acid (BHA) with the lead ion [Pb(II)] adsorbed on the cassiterite surface have been investigated by first-principles calculations due to its great significance in froth flotation. Cluster calculations show that BHA possesses the weakest chelation with Pb(II) due to the electron withdrawal ability of the benzyl ring in comparison with other hydroxamic acids. Pb(II) thermodynamically prefers to react with the cassiterite surface rather than BHA. On the other hand, the partial density of states and the atomic overlap populations have consistently verified that the adsorption of BHA results in a better symmetry in electron densities than the hydrated Pb(II). The electron density maps and the electronic localization functions have further visualized the rearrangement of the 6s2 lone pair around the lead atom. It can be concluded that the surface coordination mechanisms of Pb(II) on oxide minerals can be attributed to the coordination ability of BHA and the unique electronic structure of Pb(II), which accounts for the reported better flotation performance of the pre-assemble strategy than the pre-activating approach. This work sheds some new light on the unique coordination activation mechanism of metal ions on oxide mineral surfaces. It should be instructive to design and screen new environment-friendly flotation reagents and flotation flowsheets.

20.
Inorg Chem ; 60(5): 2878-2882, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33560825

RESUMO

A highly robust heterometallic CoIILaIII2-organic framework (NUC-19) is synthesized and features 1D rectangle-like channels with a window size of 3.4 × 6.3 Å2 and a carboxyl-group-modified inner surface. NUC-19 exhibits significantly differential uptake for C2H2, C2H4, and CH4, and the ideal adsorbed solution theory selectivities of C2H2/C2H4 (1:99, v/v) and C2H2/CH4 (50:50, v/v) at room temperature can reach up to 4.0 and 79.7, respectively. Fixed-bed dynamic breakthrough experiments under simulated industrial conditions indicate that NUC-19 could efficiently trap C2H2 from mixed gases of C2H2/CH4 and C2H2/C2H4.

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