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1.
Nano Lett ; 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38838340

ABSTRACT

Cancer immunotherapies based on cytotoxic CD8+ T lymphocytes (CTLs) are highly promising for cancer treatment. The specific interaction between T-cell receptors and peptide-MHC-I complexes (pMHC-I) on cancer cell membranes critically determines their therapeutic outcomes. However, the lack of appropriate endogenous antigens for MHC-I presentation disables tumor recognition by CTLs. By devising three antigen-loaded self-assembling peptides of pY-K(Ag)-ERGD, pY-K(Ag)-E, and Y-K(Ag)-ERGD to noncovalently generate light-activatable supramolecular antigens at tumor sites in different manners, we report pY-K(Ag)-ERGD as a promising candidate to endow tumor cells with pMHC-I targets on demand. Specifically, pY-K(Ag)-ERGD first generates low-antigenic supramolecular antigens on cancer cell membranes, and a successive light pulse allows antigen payloads to efficiently release from the supramolecular scaffold, directly producing antigenic pMHC-I. Intravenous administration of pY-K(Ag)-ERGD enables light-controlled tumor inhibition when combined with adoptively transferred antigen-specific CTLs. Our strategy is feasible for broadening tumor antigen repertoires for T-cell immunotherapies and advancing precision-controlled T-cell immunotherapies.

2.
Phys Chem Chem Phys ; 26(1): 412-420, 2023 Dec 21.
Article in English | MEDLINE | ID: mdl-38078489

ABSTRACT

Recently, MXenes, an emerging family of two-dimensional (2D) materials, have attracted increasing interest for photocatalytic water splitting due to their various excellent physical and chemical properties, such as large specific surface area, good hydrophilicity, and remarkable light absorption ability. However, the photocatalysts of MXenes with symmetric structures are limited by rapid recombination of photo-generated carriers and the prerequisite of a large band gap no less than 1.23 eV. Differently, Janus MXenes with different surface functional groups facilitate the separation of photo-generated electrons and holes with the help of the intrinsic electric field. And, at the same time, there is no prerequisite for the band gap of Janus MXene photocatalysts as long as they possess appropriate band edge positions. Here, we explored the structural, electronic and photocatalytic water splitting properties of symmetric Y2CT2 and Janus Y2CTT' MXenes (T, T' = H, F, Cl, OH) using the density functional theory (DFT) method. Our calculations show that all the investigated Y2CT2 are not suitable photocatalysts for photocatalytic water splitting at all pH values (pH = 0, 7, and 14). In contrast, all the investigated Janus Y2CTT' MXenes are good water splitting photocatalysts with high optical absorption coefficients and remarkable solar-to-hydrogen (STH) efficiencies larger than 18% at pH = 14. Moreover, the STH efficiencies are larger than 18% even at all investigated pH values for Y2CHCl (18.5-22.6%), Y2 CFCl (∼18.7%), and Y2 C(OH)Cl (∼19.4%). Based on the first-principles calculations, we here for the first time propose an easy strategy to design Janus MXene photocatalyst candidates with possible high STH efficiency according to the electronic properties of their symmetric counterparts. Our study is helpful for the future design of Janus MXenes and more generally Janus 2D photocatalysts for water splitting with high STH efficiency.

3.
Nanotechnology ; 27(14): 145701, 2016 Apr 08.
Article in English | MEDLINE | ID: mdl-26903086

ABSTRACT

P-nitrophenol (4-NP) and hydrazine hydrate are considered to be highly toxic pollutants in wastewater, and it is of great importance to remove them. Herein, TiO2-loaded Co0.85Se thin films with heterostructure were successfully synthesized by a hydrothermal route. The as-synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy and selective-area electron diffraction. The results demonstrate that TiO2 nanoparticles with a size of about 10 nm are easily loaded on the surface of graphene-like Co0.85Se nanofilms, and the NH3 · H2O plays an important role in the generation and crystallization of TiO2 nanoparticles. Brunauer-Emmett-Teller measurement shows that the obtained nanocomposites have a larger specific surface area (199.3 m(2) g(-1)) than that of Co0.85Se nanofilms (55.17 m(2) g(-1)) and TiO2 nanoparticles (19.49 m(2) g(-1)). The catalytic tests indicate Co0.85Se-TiO2 nanofilms have the highest activity for 4-NP reduction and hydrazine hydrate decomposition within 10 min and 8 min, respectively, compared with the corresponding precursor Co0.85Se nanofilms and TiO2 nanoparticles. The enhanced catalytic performance can be attributed to the larger specific surface area and higher rate of interfacial charge transfer in the heterojunction than that of the single components. In addition, recycling tests show that the as-synthesized sample presents stable conversion efficiency for 4-NP reduction.

4.
Biochemistry ; 54(13): 2177-80, 2015 Apr 07.
Article in English | MEDLINE | ID: mdl-25649784

ABSTRACT

Here we have designed and synthesized a novel analogous cis-platinum complex (TDPt) with strong two-photon absorption properties and higher stability upon laser irradiation. Interestingly, a higher cytotoxicity against three types of cancer cells compared to that of commercial cis-platinum was observed. The initial confocal micrographs showed that lysosomes may be the biological targets of such TDPt, except the conventional presumed DNA. This hypothesis was further confirmed by the two-photon microscopy and transmission electron microscopy micrograph. These results form an important basis for future "on-site observation" of the anticancer mechanism of the Pt(II) complex.


Subject(s)
Antineoplastic Agents/pharmacology , Microscopy/methods , Organoplatinum Compounds/chemistry , Organoplatinum Compounds/pharmacology , Antineoplastic Agents/chemistry , Cell Line, Tumor , Drug Design , Drug Screening Assays, Antitumor , Humans , Lysosomes/drug effects , Photons , Schiff Bases/chemistry , Spectroscopy, Near-Infrared/methods
5.
Inorg Chem ; 54(13): 6169-75, 2015 Jul 06.
Article in English | MEDLINE | ID: mdl-26046672

ABSTRACT

It is still an enormous challenge to obtain the metal-organic frameworks (MOFs) with specific properties by tuning their structures. Here we first reported that the structures of MOFs could be tuned by adding certain amount of zwitterion pyridiniumolate. To demonstrate the inductive effect, two series of assembly experiments were performed using different metal ions, namely, Cd(II) and Mn(II). The experimental results revealed that the zwitterion pyridiniumloate only acted as a structural induction agent (SIA), which did not exist in the aimed compounds. The SIAs could effectively tune the framework aperture or promote coordination and further tune the properties of MOFs without any removal or exchange after the synthesis. Therefore, the results could not only immensely expand the syntheses and structural diversity of MOFs with the fixed metal ions and organic ligands but also afford the possibility and effective convenience for tuning the properties of MOFs in the functional material research fields.

6.
Phys Chem Chem Phys ; 17(41): 27548-57, 2015 Nov 07.
Article in English | MEDLINE | ID: mdl-26427022

ABSTRACT

A facile one-step method for the synthesis of a water-soluble selenium/polypyrrole (Se/PPy) nanocomposite was developed. In the aqueous synthesis process, the pyrrole acted as a reductant for the reduction of H2SeO3, and then the elemental Se formed in situ acted as a catalyst for the polymerization of pyrrole. The characterization results show that the as-obtained composite (Se/PPy) is a spherical (Φ80 nm) product that is made up of amorphous Se particles coated by PPy layers. The formation mechanism and influence factors of the products were discussed, based on a series of experiments. It is proposed that remainder H2SeO3 adsorbed on the PPy chains increased the water-solubility and conductivity of the Se/PPy nanocomposite. Significantly, relying on the synergistic effect of photo-conductive Se nanoparticles and electric-conductive PPy molecules, the Se/PPy nanocomposite possesses a large two-photon absorption (2PA) cross-section and good optical limiting properties, which were demonstrated by the Z-scan technique using a femtosecond laser. We believe that this work should be an interesting strategy for developing polymer composites with excellent optoelectrical properties.


Subject(s)
Nanocomposites/chemistry , Polymers/chemistry , Pyrroles/chemistry , Selenium/chemistry , Water/chemistry , Catalysis , Optical Phenomena , Particle Size , Polymerization , Solubility , Surface Properties
7.
Rev Sci Instrum ; 95(2)2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38416043

ABSTRACT

Direct-conversion receivers (DCRs) have been widely used in recent years due to their small size and low power consumption. However, the mismatch between the in-phase (I) and the quadrature (Q) branches will seriously affect the performance of the DCRs. This paper proposes a novel blind compensation method to suppress the interference introduced by IQ mismatch. Based on the Hilbert transform, our proposed method can obtain the orthogonal signal of the I-channel signal by utilizing the Weaver architecture. Compared with traditional compensation methods, the main difference of the proposed method is that it ignores prior information, training sequences, and additional hardware circuits. Furthermore, the complexity of the proposed blind compensation method is low because no iterative operations are involved in the compensation process. The simulation results show that the proposed method has an excellent compensation performance, especially in wideband applications.

8.
Hum Pathol ; 143: 42-49, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38052269

ABSTRACT

Trichorhinophalangeal syndrome type 1 (TRPS1) has been reported to be a sensitive and specific immunohistochemical (IHC) marker for breast carcinomas, especially when determining primary site of origin. However, there is limited data on TRPS1 expression in prostate and bladder cancers. A two-phase study was performed with 1) an exploratory cohort analyzing TRPS1 gene alterations in prostate, bladder, and breast carcinoma and TPRS1 mRNA expression data in prostate and bladder carcinoma; and 2) TRPS1 and GATA3 IHC in a confirmatory cohort in prostate, bladder, and breast carcinoma samples. Gene alterations were identified in a subset of breast, bladder, and prostate carcinomas and mRNA was consistently detected. In the IHC cohort, 183/210 (87.1 %) of breast, 22/69 (31.9 %) of prostate, and 20/73 (27.4 %) of urothelial carcinomas showed staining with TRPS1. Intermediate to high expression of TRPS1 was observed in 173/210 (82.8 %) of breast, 17/69 (24.6 %) of prostate, and 15/73 (20.5 %) of urothelial carcinomas. Furthermore, in prostate cancer, 26.9 % of pelvic lymph node metastases and 50 % in sites of distant metastases showed expression. Increased TRPS1 mRNA expression (p = 0.032) and IHC expression (p = 0.040) correlated with worse overall survival in bladder cancer. By comparison, GATA3 IHC stained 136/210 (64.8 %) of breast, 0/69 (0 %) of prostate, and 63/73 (93 %) of bladder carcinomas. Intermediate to high expression of GATA3 was seen in 131/210 (62.4 %) of breast and 63/73 (93 %) of bladder carcinomas. This study shows there is significant staining of TRPS1 in bladder and prostate cancers. As a result, comprehensive studies are needed to establish the true specificity of TRPS1 IHC stain across various tumor types before its widespread clinical adoption.


Subject(s)
Adenocarcinoma , Breast Neoplasms , Carcinoma, Transitional Cell , Prostatic Neoplasms , Urinary Bladder Neoplasms , Male , Humans , Carcinoma, Transitional Cell/pathology , Urinary Bladder Neoplasms/pathology , Urinary Bladder/pathology , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Prostatic Neoplasms/pathology , Breast Neoplasms/pathology , Adenocarcinoma/pathology , RNA, Messenger , Muscles/metabolism , Muscles/pathology , GATA3 Transcription Factor/metabolism , Repressor Proteins/genetics
9.
J Nanosci Nanotechnol ; 13(8): 5726-31, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23882825

ABSTRACT

A rapid chemical method has been developed for the synthesis of the CdTe nanoribbons with cubic crystalline phase. The method is based on the template-engaged synthesis in which the Te nanowires were used as template reagents. On the basis of a series of experiments and characterizations, the electrochemical property of CdTe nanoribbons was determined by the voltammetric technique. Furthermore, electrochemiluminescence property of CdTe nanoribbons was investigated. The results show that CdTe nanoribbons are helpful to obtain stable electrochemiluminescence emission for 1200 seconds.

10.
Sci Total Environ ; 865: 161122, 2023 Mar 20.
Article in English | MEDLINE | ID: mdl-36587690

ABSTRACT

Fluorene (Flu) occurs widely in various environments and its toxicity to organisms is well-known. However, the impact of Flu on complicated biochemical processes involving functional microbial community has been reported rarely. In this study, the facilitation of Flu on the volatile fatty acids (VFAs) generation executed by acidogenic microbial population during sludge acidogenic fermentation (37 °C, SRT = 8 d, pH = 10.0) was investigated. The accumulation of VFAs (particularly acetic acid) increased initially and then declined with the increasing of Flu concentration (0-500 mg/kg dry sludge), which reached a maximum (3211.1 mg COD/L) as Flu content was 200 mg/kg dry sludge. The Flu-enhanced VFAs production was primarily attributed to the shift of hydrolysis/acidification, as well as the corresponding functional microbial community and the activity of enzymes. Based on the metagenomics analysis, the conversion of organic substrates, i.e. amino acid and monosaccharide, into VFAs embraced in hydrolysis/acidification shaped by Flu was constructed at the genetic level. The relative abundances of genes included in aminotransfer and deamination process of amino acid and glycolysis of monosaccharide into VFA-precursors (pyruvate, acetyl-CoA and propionyl-CoA), and the further formation of VFAs were improved due to the Flu presence. This study shed light on the Flu-affected microbial processes at the molecular biology level during acidogenic fermentation and was of great significance in resource recovery of sludge containing persistent organic pollutants.


Subject(s)
Amino Acids , Sewage , Fermentation , Sewage/chemistry , Monosaccharides , Fatty Acids, Volatile , Acids , Fluorenes , Hydrogen-Ion Concentration , Bioreactors
11.
Front Oncol ; 13: 1098943, 2023.
Article in English | MEDLINE | ID: mdl-37305568

ABSTRACT

Objectives: To explore the correlation between the incidence rates of depression and anxiety and cerebral glucose metabolism in cancer patients. Methods: The experiment subjects consisted of patients with lung cancer, head and neck tumor, stomach cancer, intestinal cancer, breast cancer and healthy individuals. A total of 240 tumor patients and 39 healthy individuals were included. All subjects were evaluated by the Hamilton depression scale (HAMD) and Manifest anxiety scale (MAS), and were examined by whole body Positron Emission Tomography/Computed Tomography (PET/CT) with 18F-fluorodeoxyglucose (FDG). Demographic, baseline clinical characteristics, brain glucose metabolic changes, emotional disorder scores and their relations were statistically analyzed. Results: The incidence rates of depression and anxiety in patients with lung cancer were higher than those in patients with other tumors, and Standard uptake values (SUVs) and metabolic volume in bilateral frontal lobe, bilateral temporal lobe, bilateral caudate nucleus, bilateral hippocampus, left cingulate gyrus were lower than those in patients with other tumors. We also found that poor pathological differentiation, and advanced TNM stage independently associated with depression and anxiety risk. SUVs in the bilateral frontal lobe, bilateral temporal lobe, bilateral caudate nucleus, bilateral hippocampus, left cingulate gyrus were negatively correlated with HAMD and MAS scores. Conclusion: This study revealed the correlation between brain glucose metabolism and emotional disorders in cancer patients. The changes in brain glucose metabolism were expected to play a major role in emotional disorders in cancer patients as psychobiological markers. These findings indicated that functional imaging can be applied for psychological assessment of cancer patients as an innovative method.

12.
Front Immunol ; 14: 1257834, 2023.
Article in English | MEDLINE | ID: mdl-37822934

ABSTRACT

Background: COVID-19 and sepsis represent formidable public health challenges, characterized by incompletely elucidated molecular mechanisms. Elucidating the interplay between COVID-19 and sepsis, particularly in geriatric patients suffering from sepsis-induced acute respiratory distress syndrome (ARDS), is of paramount importance for identifying potential therapeutic interventions to mitigate hospitalization and mortality risks. Methods: We employed bioinformatics and systems biology approaches to identify hub genes, shared pathways, molecular biomarkers, and candidate therapeutics for managing sepsis and sepsis-induced ARDS in the context of COVID-19 infection, as well as co-existing or sequentially occurring infections. We corroborated these hub genes utilizing murine sepsis-ARDS models and blood samples derived from geriatric patients afflicted by sepsis-induced ARDS. Results: Our investigation revealed 189 differentially expressed genes (DEGs) shared among COVID-19 and sepsis datasets. We constructed a protein-protein interaction network, unearthing pivotal hub genes and modules. Notably, nine hub genes displayed significant alterations and correlations with critical inflammatory mediators of pulmonary injury in murine septic lungs. Simultaneously, 12 displayed significant changes and correlations with a neutrophil-recruiting chemokine in geriatric patients with sepsis-induced ARDS. Of these, six hub genes (CD247, CD2, CD40LG, KLRB1, LCN2, RETN) showed significant alterations across COVID-19, sepsis, and geriatric sepsis-induced ARDS. Our single-cell RNA sequencing analysis of hub genes across diverse immune cell types furnished insights into disease pathogenesis. Functional analysis underscored the interconnection between sepsis/sepsis-ARDS and COVID-19, enabling us to pinpoint potential therapeutic targets, transcription factor-gene interactions, DEG-microRNA co-regulatory networks, and prospective drug and chemical compound interactions involving hub genes. Conclusion: Our investigation offers potential therapeutic targets/biomarkers, sheds light on the immune response in geriatric patients with sepsis-induced ARDS, emphasizes the association between sepsis/sepsis-ARDS and COVID-19, and proposes prospective alternative pathways for targeted therapeutic interventions.


Subject(s)
COVID-19 , Respiratory Distress Syndrome , Sepsis , Humans , Animals , Mice , Aged , Gene Expression Profiling , COVID-19/complications , COVID-19/genetics , Sepsis/complications , Sepsis/genetics , Biomarkers , Respiratory Distress Syndrome/genetics , Respiratory Distress Syndrome/complications
13.
Aging (Albany NY) ; 15(19): 10501-10523, 2023 10 06.
Article in English | MEDLINE | ID: mdl-37812215

ABSTRACT

BACKGROUND: The existing therapeutic approaches for combating tumors are insufficient in completely eradicating malignancy, as cancer facilitates tumor relapse and develops resistance to treatment interventions. The potential mechanistic connection between SARS-CoV-2 and ESCC has received limited attention. Therefore, our objective was to investigate the characteristics of SARS-CoV-2-related-genes (SCRGs) in esophageal squamous cancer (ESCC). METHODS: Raw data were obtained from the TCGA and GEO databases. Clustering of SCRGs from the scRNA-seq data was conducted using the Seurat R package. A risk signature was then generated using Lasso regression, incorporating prognostic genes related to SCRGs. Subsequently, a nomogram model was developed based on the clinicopathological characteristics and the risk signature. RESULTS: Eight clusters of SCRGs were identified in ESCC utilizing scRNA-seq data, of which three exhibited prognostic implications. A risk signature was then made up with bulk RNA-seq, which displayed substantial correlations with immune infiltration. The novel signature was verified to have excellent prognostic efficacy. CONCLUSION: The utilization of risk signatures based on SCRGs can efficiently forecast the prognosis of ESCC. A thorough characterization of the SCRGs signature in ESCC could facilitate the interpretation of ESCC's response to immunotherapy and offer innovative approaches to cancer therapy.


Subject(s)
COVID-19 , Carcinoma, Squamous Cell , Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Humans , SARS-CoV-2 , Tumor Microenvironment/genetics , Carcinoma, Squamous Cell/genetics , Carcinoma, Squamous Cell/therapy , Esophageal Neoplasms/genetics , Esophageal Neoplasms/therapy , Neoplasm Recurrence, Local/genetics , Immunotherapy , Esophageal Squamous Cell Carcinoma/genetics , Esophageal Squamous Cell Carcinoma/therapy , Prognosis
14.
J Nanosci Nanotechnol ; 12(10): 7980-5, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23421167

ABSTRACT

Direct electrochemistry of hemoglobin (Hb) was successfully fabricated by immobilizing Hb on the nanocomposites containing of Ag@C nanocables and Au nanoparticles (AuNPs) modified glassy carbon electrode (GCE). The immobilized Hb retained its biological activity and shown high catalytic activities to the reduction of H2O2 by circular dicroism (CD) spectrum, fourier transform infrared (FT-IR) spectrum and cyclic voltammetry (CV). Experimental conditions such as scan rate and pH Value were studied and optimized. The results indicated that the resulting biosensor are linear to the concentrations of H2O2 in the ranges of 6.67 x 10(-7)-2.40 x 10(5) M, and the detection limit is 2.02 x 10(-7) M. The electrochemical biosensor has also high stability and good reproducibility.


Subject(s)
Electrochemistry/methods , Gold/chemistry , Hemoglobins/chemistry , Metal Nanoparticles , Catalysis , Circular Dichroism , Hydrogen Peroxide/chemistry , Reproducibility of Results , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
15.
J Med Chem ; 65(4): 3597-3605, 2022 02 24.
Article in English | MEDLINE | ID: mdl-35148084

ABSTRACT

Internal tandem duplication in the FLT3 receptor tyrosine kinase (FLT3/ITD mutation) occurs in approximately 25% of acute myeloid leukemia (AML) patients. To specifically target this driver mutation in AML, we assessed and compared the cell-based cytotoxicity of a diversity library (10,000 compounds) against the normal cell line BaF3 and the isogenic leukemic cell line BaF3/ITD. A benzoimidazole scaffold-based compound (HP1142) was identified as the most selective compound against a series of murine and human leukemia cells with FLT3/ITD. Novel benzoimidazole compounds were further designed to improve the aqueous solubility of HP1142. The most potent compound, HP1328, demonstrated desirable pharmaceutical and pharmacokinetic properties. Treatment with HP1328 significantly reduced the leukemia burden and prolonged the survival of mice with FLT3/ITD leukemia. Our findings establish the specific activity of the benzoimidazole compound against FLT3/ITD leukemia and warrant further investigation in this subset of leukemia patients with poor prognosis.


Subject(s)
Antineoplastic Agents/pharmacology , Benzimidazoles/pharmacology , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Benzimidazoles/chemistry , Benzimidazoles/pharmacokinetics , Cell Line , Cell Line, Tumor , High-Throughput Screening Assays , Humans , Leukemia/drug therapy , Male , Mice , Mice, Inbred BALB C , Protein Kinase Inhibitors/pharmacology , Rats , Rats, Sprague-Dawley , Small Molecule Libraries , Solubility , Xenograft Model Antitumor Assays
16.
Inorg Chem ; 50(17): 7997-8006, 2011 Sep 05.
Article in English | MEDLINE | ID: mdl-21827147

ABSTRACT

Two bis-ß-diketones, RCOCH(2)CO-EPTZ-COCH(2)COR (EPTZ = 10-ethylphenothiazine; R = C(6)H(5) for H(2)L(1) and CF(3) for H(2)L(2)) and their cyclic dinuclear Zn(II), Cd(II), Ni(II), Mn(II), Cu(II), Co(II) complexes have been synthesized and fully characterized. Their crystal structures were determined by single crystal X-ray diffraction analysis. Their photophysical properties have been further investigated both experimentally and theoretically. The results revealed that significant enhancement of two-photon absorption cross section values were obtained for the cyclic dinuclear Zn(II) and Cd(II) complexes compared with their free ligands. Additionally, confocal microscopy and two-photon microscopy fluorescent imaging of MCF-7 cells labeled with two ligands and Zn(II) complexes reveal their potential applications as a biological fluorescent probe.


Subject(s)
Antineoplastic Agents/pharmacology , Fluorescent Dyes/pharmacology , Ketones/chemistry , Metals, Heavy/chemistry , Organometallic Compounds/pharmacology , Phenothiazines/chemistry , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Survival/drug effects , Chemistry Techniques, Synthetic , Crystallography, X-Ray , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Ligands , Models, Molecular , Molecular Conformation , Organometallic Compounds/chemical synthesis , Organometallic Compounds/chemistry , Photochemical Processes , Quantum Theory , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, Cultured
17.
J Nanosci Nanotechnol ; 11(3): 2064-9, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21449350

ABSTRACT

A novel hydrothermal method has been developed for the preparation of Bi2Se3 nanotubes with the laminar surface. The method is based on the template-engaged synthesis in which the as-prepared Se nanotubes were used as template reagent. The morphology, constitution and crystalline phase of the products as-obtained were characterized by SEM, XRD and XPS. On the basis of a series of experiments and characterizations, the effect factors (such as the reaction temperature and the atom ratio of Bi and Se in the precursors) and the formation mechanism of the Bi2Se3 nanotubes were discussed. Furthermore, the electrochemical property of the Bi2Se3 nanotubes was determined by the voltammetric technique, and the significant results were obtained.


Subject(s)
Bismuth/chemistry , Crystallization/methods , Nanotubes/chemistry , Nanotubes/ultrastructure , Selenium/chemistry , Electric Conductivity , Materials Testing , Molecular Conformation , Nanotechnology/methods , Particle Size , Surface Properties
18.
Front Bioeng Biotechnol ; 9: 605171, 2021.
Article in English | MEDLINE | ID: mdl-33842443

ABSTRACT

Magnesium (Mg) and its alloys have attached more and more attention because of their potential as a new type of biodegradable metal materials. In this work, AZ31/ZrO2 nanocomposites with good uniformity were prepared successfully by friction stir processing (FSP). The scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to characterize the microstructure of the composites. The mechanical properties, electrochemical corrosion properties and biological properties were evaluated. In addition, the effect of reinforced particles (ZrO2) on the microstructure and properties of the composite was studied comparing with FSP AZ31 Mg alloy. The results show that compared with the base metal (BM), the AZ31/ZrO2 composite material achieves homogenization, densification, and grain refinement after FSP. The combination of dynamic recrystallization and ZrO2 particles leads to grain refinement of Mg alloy, and the average grain size of AZ31/ZrO2 composites is 3.2 µm. After FSP, the c-axis of grain is deflected under the compression stress of shoulder and the shear stress of pin. The ultimate tensile strength (UTS) and yield strength (YS) of BM were 283 and 137 MPa, respectively, the UTS and YS of AZ31/ZrO2 composites were 427 and 217 MPa, respectively. The grain refinement and Orowan strengthening are the major strengthening mechanisms. Moreover, the corrosion resistance in simulated body fluid of Mg alloy is improved by grain refinement and the barrier effect of ZrO2.

19.
J Am Chem Soc ; 131(14): 5208-13, 2009 Apr 15.
Article in English | MEDLINE | ID: mdl-19317489

ABSTRACT

A novel sulfur-terminal Zn(II) complex Zn(S)(2)L (L = N-hexyl-3-{2-[4-(2,2':6',2''-terpyridin-4'-yl)phenyl] ethenyl}carbazole) was obtained by a facile solvothermal process. The unique feature in this new reaction design is the use of ZnS nanocrystals as a precursor and bulky chromophoric L as an ancillary ligand. The versatility of the two terminal sulfur atoms is relevant to biological system. The resulting Zn(S)(2)L complex shows two-photon excited fluorescence (TPEF), which has been proven to be potentially useful for two-photon microscopy imaging in living cells. In addition, cytotoxicity tests showed that the low-micromolar concentrations of Zn(S)(2)L did not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies.


Subject(s)
Fluorescent Dyes/chemical synthesis , Metal Nanoparticles/chemistry , Microscopy, Fluorescence/methods , Sulfur/chemistry , Zinc/chemistry , Cell Survival , Fluorescent Dyes/chemistry , Fluorescent Dyes/toxicity , HeLa Cells , Humans , Metal Nanoparticles/toxicity , Molecular Structure , Photons , Sulfur/toxicity , Zinc/toxicity
20.
Anal Chem ; 81(11): 4476-81, 2009 Jun 01.
Article in English | MEDLINE | ID: mdl-19402619

ABSTRACT

In this paper, we report the IR (infrared) CVA (cyclic voltabsorptometry) and DCVA (derivative cyclic voltabsorptometry) spectroelectrochemical techniques to elucidate an electrochemical mechanism. First we set potassium ferrocyanide as an example to explain the validity of this method. Then the electrochemical redox of two compounds, 1,4-benzoquinone and 1,4-bis(2-ferrocenylvinyl)benzene, was selected to be examined with this method. 1,4-Benzoquinone exhibits two single-electron waves in the cyclic voltammetric (CV) experiment, whereas two electroactive groups (Fc) are contained in p-(Fc-CH=CH)(2)BZ, but only one redox wave is observed. IR CVA results show that three IR absorption peaks in 1,4-benzoquinone, 1232 cm(-1) (the absorption of final production), 1656 cm(-1) (the absorption of original reactant), and 1510 cm(-1) (the absorption of intermediate), and two IR absorption peaks in 1,4-bis(2-ferrocenylvinyl)benzene, 1620 cm(-1) (the absorption of final oxide production) and 1589 cm(-1) (the absorption of intermediate), can be used to track the electron transfer. On the basis of the IR absorbance at the appropriate monitored wavelength (mentioned above), we can analyze simultaneously the concentration change of the corresponding redox transition during CV scans. Also the combination of the DCVA spectroelectrochemical technique with theory analysis allows reconstructing the current-potential (i-E) curve for each step of electron transfer. The reconstructed i-E curve can help us to understand the electron-transfer process. We believe IR CVA and DCVA spectroelectrochemical techniques can be applicable to the study of a wide range of complex electrochemistry processes.

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