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1.
Inorg Chem ; 2022 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-34978442

RESUMO

A tubelike Zn(II)-Yb(III) cluster, [Zn6Yb5L5(HL)(NO3)4(DMF)6(EtOH)4(H2O)4] (1; DMF = N,N-dimethylformamide and EtOH = ethanol; molecular size 1.5 × 1.8 × 2.9 nm), was synthesized from a new long-chain Schiff base ligand. 1 exhibits a regulatable near-IR-luminescent response to nitrofuran antibiotics (NFAs) and fluoroquinolones with high sensitivity, which is not influenced by other antibiotics. The quenching constants of NFAs and fluoroquinolones range from 0.55 × 104 to 8.8 × 104 M-1, and the detection limits of 1 to them are from 4.2 × 10-4 to 2.6 × 10-5 M. It also shows a luminescent response to real antibiotic drugs containing NFAs and fluoroquinolones.

2.
Carbohydr Polym ; 275: 118701, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742427

RESUMO

Most cellulose products lack water resistance due to the existence of abundant hydroxyl groups. In this work, microfibrillated cellulose (MFC) was modified via 3-aminopropyltriethoxysilane (APTES)-assisted ball milling. Under the synergism between high-energy mechanical force field and APTES-modification, the fibrillation and hydrophobization of MFC were achieved simultaneously. Free-standing translucent cellulose films made of modified MFC were fabricated. The original crystal form of cellulose is maintained. The hydrophobicity of cellulose film markedly increases and the water contact angle goes up to 133.2 ± 3.4°, which might be ascribed to the combined effects of APTES-modification and rough film surface. In addition, the thermostability and mechanical properties of cellulose film are also improved via mechanochemical modification. This work provides a novel one-step fibrillation-hydrophobization method for cellulose.

3.
J Hazard Mater ; 424(Pt A): 127388, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-34879578

RESUMO

Mercuric Hg(II) ion forms exceptionally strong complexes with various organic ligands, particularly thiols and dissolved organic matter (DOM) in natural water. Few studies, however, have experimentally determined whether or not the presence of base cations and transition metal ions, such as Ca(II), Cu(II), and Zn(II), would compete with Hg(II) bound to these ligands, as concentrations of these metal ions are usually orders of magnitude higher than Hg(II) in aquatic systems. Different from previous model predictions, a significant fraction of Hg(II) bound to cysteine (CYS), glutathione (GSH), or DOM was found to be competitively exchanged by Cu(II), but not by Zn(II) or Ca(II). About 20-75% of CYS-bound-Hg(II) [at 2:1 CYS:Hg(II)] and 14-40% of GSH-bound-Hg(II) [at 1:1 GSH:Hg(II)] were exchanged by Cu(II) at concentrations 1-3 orders of magnitude greater than Hg(II). Competitive exchange was also observed between Cu(II) and Hg(II) bound to DOM, albeit to a lower extent, depending on relative abundances of thiol and carboxylate functional groups on DOM and their equilibrium time with Hg(II). When complexed with ethylenediaminetetraacetate (EDTA), most Hg(II) could be exchanged by Cu(II) and Zn(II), as well as Ca(II) at increasing concentrations. These results shed additional light on competitive exchange reactions between Hg(II) and coexisting metal ions and have important implications in Hg(II) chemical speciation and biogeochemical transformation, particularly in contaminated environments containing relatively high concentrations of Hg(II) and metal ions.

4.
J Phys Chem A ; 126(1): 125-144, 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-34935392

RESUMO

We report the results on the combustion of single, levitated droplets of exo-tetrahydrodicyclopentadiene (JP-10) doped with titanium-aluminum-boron (Ti-Al-B) reactive metal nanopowders (RMNPs) in an oxygen (60%)-argon (40%) atmosphere by exploiting an ultrasonic levitator with droplets ignited by a carbon dioxide laser. Ultraviolet-visible (UV-vis) emission spectroscopy revealed the presence of gas-phase aluminum (Al) and titanium (Ti) atoms. These atoms can be oxidized in the gas phase by molecular oxygen to form spectroscopically detected aluminum monoxide (AlO) and titanium monoxide (TiO) transients. Analysis of the optical ignition videos supports that the nanoparticles are ignited before JP-10. The detection of boron monoxide (BO) further proposes an active surface chemistry through the oxidation of the RMNPs and the release of at least BO into the gas phase. The oxidation of gas-phase BO by molecular oxygen to boron dioxide (BO2) plus atomic oxygen might operate in the gas phase, although the involvement of surface oxidation processes of RMNPs to BO2 cannot be discounted. The UV-vis emission spectra also revealed the key reactive intermediates (OH, CH, C2, and HCO) of the oxidation of JP-10. Electronic structure calculations reveal that the presence of reactive radicals has a profound impact on the oxidation of JP-10. Although titanium monoxide (TiO) reacts to produce titanium dioxide (TiO2), it does not engage in an active JP-10 chemistry as all abstraction pathways are endoergic by more than 217 kJ mol-1. This is similar for atomic aluminum and titanium, whose hydrogen abstraction reactions from JP-10 were revealed to be endoergic by at least 77 kJ mol-1. Therefore, aluminum and titanium react preferentially with molecular oxygen to produce their monoxides. However, the formation of BO, AlO, and BO2 supplies a pool of highly reactive radicals, which can abstract hydrogen from JP-10 via transition states ranging from only 1 to 5 kJ mol-1 above the separated reactants, forming JP-10 radicals along with the hydrogen abstraction products (boron hydride oxide, aluminum monohydroxide, and metaboric acid) in the overall exoergic reactions. These abstraction barriers are well below the barriers of abstractions for ground-state atomic oxygen and molecular oxygen. In this sense, gas-phase BO, AlO, and BO2 catalyze the oxidation of gas-phase JP-10 via hydrogen abstraction, forming highly reactive JP-10 radicals. Overall, the addition of RMNPs to JP-10 not only provides a higher energy density fuel but is also expected to lead to shorter ignition delays compared to pure JP-10 due to the highly reactive pool of radicals (BO, AlO, and BO2) formed in the initial stage of the oxidation process.

5.
J Org Chem ; 2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34866383

RESUMO

The base-induced formal [4+3] annulation reaction of in situ-formed aza-o-quinone methides and pyridinium 1,4-zwitterionic thiolates is reported. This protocol provides a novel and reliable method for the synthesis of biologically interesting benzo[e][1,4]thiazepine derivatives in synthetically useful yields. In addition, postsynthetic modification results in the formation of its sulfoxide and sulfone derivatives.

6.
Phytochemistry ; 195: 113026, 2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34890886

RESUMO

Phytochemical investigation of the ethanol extract from wild Momordica charantia vines has resulted in isolation of seven cucurbitane-type triterpenoids, including six undescribed compounds, kuguaovins H‒M, and the known compound, momordicoside K. The structures of the isolated compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, and MS experiments. The chemical structure of momordicoside K was determined for the first time by X-ray crystallographic analysis and its absolute configuration assigned. The cytotoxicity against four human tumor cell lines and anti-inflammatory activities on LPS-stimulated RAW264.7 macrophages were evaluated. Of the isolates, kaguaovin L exhibited potential cytotoxicity against MCF-7, HEp-2, Hep-G2, and WiDr cancer cell lines and showed moderate anti-NO production activity. In addition, kuguaovins H and J also showed the stimulatory effect of GLP-1 secretion on the murine intestinal secretin tumor cell line (STC-1).

7.
Front Plant Sci ; 12: 692715, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34956247

RESUMO

Non-structural carbohydrates (NSCs) facilitate plant adaptation to drought stress, characterize tree growth and survival ability, and buffer against external disturbances. Previous studies have focused on the distribution and dynamics of NSCs among different plant organs under drought conditions. However, discussion about the NSC levels of fine roots in different root branch orders is limited, especially the relationship between fine root trait variation and NSC content. The objective of the study was to shed light on the synergistic variation in fine root traits and NSC content in different root branch orders under different drought and soil substrate conditions. The 2-year-old Fraxinus mandshurica Rupr. potted seedlings were planted in three different soil substrates (humus, loam, and sandy-loam soil) and subjected to four drought intensities (CK, mild drought, moderate drought, and severe drought) for 2 months. With increasing drought intensity, the biomass of fine roots decreased significantly. Under the same drought intensity, seedlings in sandy-loam soil had higher root biomass, and the coefficient of variation of 5th-order roots (37.4, 44.5, and 53% in humus, loam, and sandy-loam soil, respectively) was higher than that of lower-order roots. All branch order roots of seedlings in humus soil had the largest specific root length (SRL) and specific root surface area (SRA), in addition to the lowest diameter. With increasing drought intensity, the SRL and average diameter (AD) of all root branch orders increased and decreased, respectively. The fine roots in humus soil had a higher soluble sugar (SS) content and lower starch (ST) content compared to the loam and sandy-loam soil. Additionally, the SS and ST contents of fine roots showed decreasing and increasing tendencies with increasing drought intensities, respectively. SS and ST explained the highest degree of the total variation in fine root traits, which were 32 and 32.1%, respectively. With increasing root order, the explanation of the variation in root traits by ST decreased (only 6.8% for 5th-order roots). The observed response in terms of morphological traits of different fine root branch orders of F. mandshurica seedlings to resource fluctuations ensures the maintenance of a low cost-benefit ratio in the root system development.

8.
Adv Mater ; : e2109198, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34951494

RESUMO

The rapid development of 3D printing has led to considerable progress in the field of biomedical engineering. Notably, 4D printing provides a potential strategy to achieve a time-dependent physical change within tissue scaffolds or replicate the dynamic biological behaviors of native tissues for smart tissue regeneration and the fabrication of medical devices. The fabricated stimulus-responsive structures can offer dynamic, reprogrammable deformation or actuation to mimic complex physical, biochemical, and mechanical processes of native tissues. Although there has been notable progress made in the development of the 4D printing approach for various biomedical applications, its more broad-scale adoption for clinical use and tissue engineering purposes has been complicated by a notable limitation of printable smart materials and the simplistic nature of achievable responses possible with current sources of stimulation. In this review, we highlight the recent progress made in the field of 4D printing by discussing the various printing mechanisms that have been achieved with great emphasis on smart ink mechanisms of 4D actuation, construct structural design, and printing technologies. We then summarize recent 4D printing studies which focus on the applications of tissue/organ regeneration and medical devices. Finally, the current challenges and future perspectives of 4D printing are also discussed. This article is protected by copyright. All rights reserved.

9.
J Biophotonics ; : e202100252, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34817116

RESUMO

Optoretinogram, a technique in which optical coherence tomography (OCT) is used to measure retinal functions in response to a visible light stimulus, can be a potentially useful tool to quantify retinal health alterations. Existing experimental studies on animals have focused on measuring the global retinal response by transversally averaging 3D data across the retina, which minimizes the spatial resolution of the signals, and limits the signal-to-noise ratio because only central B-scans are collected and analyzed. These problems were addressed in this study by collecting volumetric data to probe functional signals and developing an improved 3D registration approach to align such series-acquired OCT volumes. These data were then divided into small blocks and subject to a spatiotemporal analysis, whose results confirmed the spatial-dependence of functional signals. By further averaging, the overall measurement accuracies for the position and the scattering signals were estimated to be approximately 30 nm and 1.1 %, respectively. With improved accuracy, this method revealed certain novel functional signals that have not been previously reported. In conclusion, this work provides a powerful tool to monitor retinal local and global functional changes in aging, diseased, or treated rodent eyes.

10.
PeerJ ; 9: e12328, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34820167

RESUMO

Juglans mandshurica Maxim is a hermaphroditic plant belonging to the genus Juglans in the family Juglandaceae. The pollination period of female flowers is different from the loose powder period of male flowers on the same tree. In several trees, female flowers bloom first, whereas in others, male flowers bloom first. In this study, male and female flower buds of J. mandshurica at the physiological differentiation stage were used. Illumina-based transcriptome sequencing was performed, and the quality of the sequencing results was evaluated and analyzed. A total of 138,138 unigenes with an average length of 788 bp were obtained. There were 8,116 differentially expressed genes (DEGs); 2,840 genes were upregulated, and 5,276 genes were downregulated. The DEGs were classified by Gene Ontology and analyzed by Kyoto Encyclopedia of Genes and Genomes. The signal transduction factors involved in phytohormone synthesis were selected. The results displayed that ARF and SAUR were expressed differently in the auxin signaling pathway. Additionally, DELLA protein (a negative regulator of gibberellin), the cytokinin synthesis pathway, and A-ARR were downregulated. On April 2nd, the contents of IAA, GA, CTK, ETH and SA in male and female flower buds of two types of J. mandshurica were opposite, and there were obvious genes regulating gender differentiation. Overall, we found that the sex differentiation of J. mandshurica was related to various hormone signal transduction pathways, and hormone signal transduction plays a leading role in regulation.

11.
J Cell Mol Med ; 25(23): 10939-10949, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34734681

RESUMO

Antibody-mediated rejection (AMR) is one of the most dominant mechanisms responsible for the loss of kidney grafts. Previous researches have shown that donor-specific antibodies (DSAs) are the major mediators of AMR. In order to prolong the survival time of grafts, it is vital to reduce the incidence of AMR and inhibit the generation of DSAs. We established an animal model of AMR by performing kidney transplantation in pre-sensitized rats. Then, we investigated the effect of bortezomib (BTZ) on AMR. We found that BTZ could reduce the serum level of DSAs and alleviate post-transplantation inflammation in peritubular capillaries (PTCs) and glomeruli, which was demonstrated by the reduction of C4d and IgG deposition in PTCs, and the reduced number of B cell and plasma cell in peripheral blood and the transplanted kidney (p < 0.05). Our results also suggested that BTZ increased the number of regulatory T cell (Treg) and significantly reduced the proportion of T helper (Th17) cell (p < 0.05). Besides, BTZ induced the significant upregulation of anti-inflammatory cytokines but downregulated pro-inflammatory cytokines (p < 0.05). After dealing with Atg5 siRNA-lentivirus, the effect of BTZ alleviating AMR was reversed and Th17/Treg proportions were also significantly modulated. Collectively, these findings show that BTZ slows down the process of AMR and Atg5 may be the key mechanism. Furthermore, Atg5 silencing results may be demonstrated that Atg5 alleviated AMR by modulating the ratio of Th17/Treg.

12.
Arthritis Res Ther ; 23(1): 279, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34736521

RESUMO

BACKGROUND: Dysregulation of T cells mediated immune responses is a hallmark in the development of systemic lupus erythematosus (SLE). Recent genome wide association study (GWAS) revealed the genetic contribution of variants located in the cytotoxic T lymphocyte-associated protein-4 (CTLA4)-inducible T cell co-stimulator (ICOS) intergenic region to SLE susceptibility. Our aim is to find a functional variant in this region. METHODS: The genetic association results in the CTLA4-ICOS region from previous GWAS were adopted to select the potential variant which was further replicated in two independent cohorts (Henan cohort 2053 SLE patients and 1845 healthy controls, Beijing cohort 2303 SLE patients and 19,262 healthy). In order to explore the functional significance in SLE, bioinformatics with validation experiments (including electrophoretic mobility shift assay and luciferase reporter assay) and mRNA expression analysis were also performed. RESULTS: A variant located in the CTLA4-ICOS intergenic region, rs17268364, was associated with susceptibility to SLE patients in Chinese populations (risk allele, pmeta = 7.02×10-11, OR 1.19, 95%CI 1.13-1.26). The bioinformatics suggested that rs17268364 might affect the expression of CTLA4, not ICOS. The rs17268364 risk G allele containing sequence reduced the expression of the reporter gene by binding transcriptional repressor Ewing sarcoma breakpoint region 1 (EWSR1). Following genotype-mRNA expression, the analysis also showed the risk allele of rs17268364 was associated with low CTLA4 expression in lupus nephritis (LN) patients. Healthy individuals carrying rs17268364 risk G allele was significantly correlated with higher levels of IFN-α signature including increased lymphocyte antigen 6E (LY6E) (p=0.031), interferon-stimulated gene 15 (ISG15) (p=0.038), interferon regulatory factor 9 (IRF9) (p=0.028), and interferon regulatory factor 5 (IRF5) (p=0.040) mRNA expression. CONCLUSIONS: The present study confirmed the functional role of rs17268364 in the CTLA4-ICOS intergenic region that increased SLE susceptibility in the Chinese population.


Assuntos
Estudo de Associação Genômica Ampla , Lúpus Eritematoso Sistêmico , Alelos , Antígeno CTLA-4/genética , Estudos de Casos e Controles , Predisposição Genética para Doença/genética , Genótipo , Humanos , Fatores Reguladores de Interferon , Lúpus Eritematoso Sistêmico/genética , Polimorfismo de Nucleotídeo Único/genética , Proteína EWS de Ligação a RNA
13.
China CDC Wkly ; 3(20): 430-433, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34594906

RESUMO

What is already known about this topic? Brucellosis is one of the most important zoonotic diseases in China. Goat milk and dairy products are essential pathways for foodborne transmission of brucellosis. Pasteurization can completely kill Brucellaspp. in milk, and milk-borne transmission is mainly related to unhealthy dietary hygiene habits and insufficient epidemic control among animals. What is added by this report? This epidemic is the first outbreak of brucellosis in Zhangping City, Fujian Province. A total of 6 confirmed cases were found, and the onset time was from April to June 2019. The investigation suggested that the transmission chain of the epidemic included a private butcher, an infected goat from the north, a dairy farmer, close contact spread, unsterilized goat milk, and consumers drinking raw goat milk. What are the implications for public health practices? For the non-endemic area of brucellosis, preventing the import of infected animals and enhancing the practitioner's and the public's awareness of disease prevention has important public health significance. It is necessary to strengthen the transregional quarantine of livestock, the food safety inspection and management, and the practitioners' and public's awareness of food safety.

14.
China CDC Wkly ; 3(26): 557-561, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34594935

RESUMO

Introduction: National Notifiable Disease Reporting System (NNDRS) plays an important role in the early detection and control of tuberculosis (TB) in China. This study analyzed the epidemiological characteristics of pulmonary tuberculosis (PTB) in Kashgar Prefecture, Xinjiang Uygur Autnomous Region, China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS, which included the geographical distribution, age, sex, occupation, and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020. Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results: There were 189,416 PTB cases reported during 2011-2020, with a mean annual PTB case notification rate (CNR) of 451.29/100,000. A rising trend in the rate of reported PTB between 2011 and 2017 (χ 2 trend=26.09, P<0.01) and a declining trend between 2018 and 2020 (χ 2 trend=314.44, P<0.01) were observed. The months with the highest reported number of PTB cases were March to May and November to December. The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females. In addition, 19.76% of patients were bacteriologically-confirmed (Bac+) cases (37,425/189,416), and the mean annual Bac+ CNR was 89.17/100,000, rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020 (χ 2 trend=74.44, P<0.01).Conclusions: The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years. Males, elderly population, winter and spring, and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar. Targeted prevention and treatment of TB should be strengthened in key groups in this region.

15.
China CDC Wkly ; 3(6): 110-113, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34595015

RESUMO

What is already known about this topic? Wulanchabu City Center for Endemic Disease Prevention and Control had established and used a Brucellosis Integrated Information System (BIIS) since 2013. However, it had not been systematically evaluated and promoted so far. What is added by this report? The BIIS had significantly improved the efficiency of brucellosis reporting and provided convenience for follow-up management of cases, which was valuable for finishing completely routine therapy. However, the stability of the system needs to be improved. What are the implications for public health practice? The results of the BIIS assessment demonstrated its advantages and disadvantages, which could provide some evidence for its implementation in other areas of China.

16.
Front Cardiovasc Med ; 8: 716822, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34660718

RESUMO

Vascular calcification, a common pathological phenomenon in atherosclerosis, diabetes, hypertension, and other diseases, increases the incidence and mortality of cardiovascular diseases. Therefore, the prevention and detection of vascular calcification play an important role. At present, various techniques have been applied to the analysis of vascular calcification, but clinical examination mainly depends on non-invasive and invasive imaging methods to detect and quantify. Computed tomography (CT), as a commonly used clinical examination method, can analyze vascular calcification. In recent years, with the development of technology, in addition to traditional CT, some emerging types of CT, such as dual-energy CT and micro CT, have emerged for vascular imaging and providing anatomical information for calcification. This review focuses on the latest application of various CT techniques in vascular calcification.

17.
Comput Methods Programs Biomed ; 212: 106439, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34695734

RESUMO

BACKGROUND AND OBJECTIVE: Early diagnoses and rational therapeutics of glomerulopathy can control progression and improve prognosis. The gold standard for the diagnosis of glomerulopathy is pathology by renal biopsy, which is invasive and has many contraindications. We aim to use renal ultrasonography for histologic classification of glomerulopathy. METHODS: Ultrasonography can present multi-view sections of kidney, thus we proposed a multi-view and cross-domain integration strategy (CD-ConcatNet) to obtain more effective features and improve diagnosis accuracy. We creatively apply 2D group convolution and 3D convolution to process multiple 2D ultrasound images and extract multi-view features of renal ultrasound images. Cross-domain concatenation in each spatial resolution of feature maps is applied for more informative feature learning. RESULTS: A total of 76 adult patients were collected and divided into training dataset (56 cases with 515 images) and validation dataset (20 cases with 180 images). We obtained the best mean accuracy of 0.83 and AUC of 0.8667 in the validation dataset. CONCLUSION: Comparison experiments demonstrate that our designed CD-ConcatNet achieves the best classification performance and has great superiority on histologic types diagnosis. Results also prove that the integration of multi-view ultrasound images is beneficial for histologic classification and ultrasound images can indeed provide discriminating information for histologic diagnosis.


Assuntos
Ultrassonografia , Humanos
18.
J Mater Chem B ; 9(37): 7608-7632, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34586145

RESUMO

Nature's material systems during evolution have developed the ability to respond and adapt to environmental stimuli through the generation of complex structures capable of varying their functions across direction, distances and time. 3D printing technologies can recapitulate structural motifs present in natural materials, and efforts are currently being made on the technological side to improve printing resolution, shape fidelity, and printing speed. However, an intrinsic limitation of this technology is that printed objects are static and thus inadequate to dynamically reshape when subjected to external stimuli. In recent years, this issue has been addressed with the design and precise deployment of smart materials that can undergo a programmed morphing in response to a stimulus. The term 4D printing was coined to indicate the combined use of additive manufacturing, smart materials, and careful design of appropriate geometries. In this review, we report the recent progress in the design and development of smart materials that are actuated by different stimuli and their exploitation within additive manufacturing to produce biomimetic structures with important repercussions in different but interrelated biomedical areas.

19.
Adv Mater ; 33(45): e2105079, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34541723

RESUMO

Understanding the growth mechanisms of 2D van der Waals (vdW) heterostructures is of great importance in exploring their functionalities and device applications. A custom-built system integrating physical vapor deposition and optical microscopy/Raman spectroscopy is employed to study the dynamic growth processes of 2D vdW heterostructures in situ. This allows the identification of a new growth mode with a distinctly different growth rate and morphology from those of the conventional linear growth mode. A model that explains the difference in morphologies and quantifies the growth rates of the two modes by taking the role of surface diffusion into account is proposed. A range of material combinations including CdI2 /WS2 , CdI2 /MoS2 , CdI2 /WSe2 , PbI2 /WS2 , PbI2 /MoS2 , PbI2 /WSe2 , and Bi2 Se3 /WS2 is systematically investigated. These findings may be generalized to the synthesis of many other 2D heterostructures with controlled morphologies and physical properties, benefiting future device applications.

20.
Water Res ; 204: 117622, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34507023

RESUMO

To alleviate algal fouling in membrane water treatment processes, conventional technologies such as coagulation with poly aluminum chloride (PACl) has been widely adopted by many drinking water treatment plants. However, coagulation alone exhibited relatively weak removal effect for algal pollutants, and the coagulant residues due to the excess dosage also raised concerns. Thus, a novel process of coupling sodium percarbonate (SPC) oxidation and PACl coagulation was proposed, integrated with membrane filtration for algae-laden water treatment. The dosages of PACl and SPC were optimized, and the SPC dosing strategies were systematically compared. The changes in the characteristics of algal pollutants were investigated, and the results revealed that the resistance of algal foulants to aggregation was decreased, and the particle size of algal foulants became larger. With the synergism of coagulation and oxidation, the degradation of fluorescent organics was strengthened, and macromolecular biopolymers were decomposed into low molecular weight organics. The fouling control efficiency was further explored, and the results indicated that both irreversible and reversible fouling were effectively controlled, among which PACl/SPC (simultaneous treatment) performed best with the irreversible fouling reduced by 90.5%, while the efficiency of SPC-PACl (SPC followed by PACl) was relatively lower (57.3%). The fouling mechanism was altered by slowing the formation of cake filtration, and the reduction of algal cells played a more important role for the fouling alleviation. The interface properties of contaminated membranes (i.e., functional groups, images, and micromorphology) were characterized, and the efficiency of the proposed strategy was further verified. The proposed strategy exhibits great application values for improving membrane performance during algae-laden water treatment.


Assuntos
Filtração , Purificação da Água , Carbonatos , Membranas , Oxirredução
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