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1.
Inorg Chem ; 63(21): 10022-10030, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38748907

ABSTRACT

In this work, phase-pure Mg1.8(Ni1-xCox)0.2Al4Si5O18 (0 ≤ x ≤ 1) ceramics were synthesized by a high-temperature solid-state method. On the basis of Rietveld refinement data of X-ray powder diffraction and Phillips-Vechten-Levine theory, the atomic ionicity, lattice energy, and bond energy of the compound were calculated to explore their influence on the microwave dielectric properties of ceramics. The Mg1.8Ni0.1Co0.1Al4Si5O18 (x = 0.5) ceramic exhibited the best microwave dielectric properties: εr = 4.44, Qf = 73 539 GHz@13 GHz, and τf = -23.9 ppm/°C. (Ni1-xCox)2+ complex ionic doping, compared with only Ni2+ or Co2+, is beneficial for improving the symmetry of [Si4Al2O18] hexagonal rings and reducing distortion. Subsequently, 8 wt % TiO2 was added to Mg1.8Ni0.1Co0.1Al4Si5O18, resulting in a near-zero τf and high Qf values for the composite ceramic, with εr = 5.22, Qf = 58 449 GHz@13 GHz, and τf = -2.06 ppm/°C. Finally, a 5G millimeter-wave antenna with a central operating frequency of 25.52 GHz was designed and fabricated using the Mg1.8Ni0.1Co0.1Al4Si5O18-8 wt % TiO2 ceramics. Operating in the 24.7-26.0 GHz range, it demonstrated favorable radiation characteristics with a simulated efficiency of 85.2% and a gain of 4.58 dBi. The antenna's performance confirms the high potential of the cordierite composite for application in 5G communication systems.

2.
Research (Wash D C) ; 6: 0208, 2023.
Article in English | MEDLINE | ID: mdl-37719048

ABSTRACT

Acoustically actuated magnetoelectric (ME) antenna based on the efficient oscillation of magnetic dipoles has recently been considered as a promising solution for portable very-low-frequency communications. However, the severe nonlinear dynamic behavior in the case of strong-field excitation results in insufficient radiation capability and poor communication performance for a conventional ME antenna. In this work, we propose to suppress the nonlinearity of an ME antenna by neutralizing the spring-hardening effect in amorphous Metglas and the spring-softening effect in piezoelectric ceramics through an ME multilayered transmitter (ME-MLTx) design. With a driving voltage of 50 Vpp at the resonance frequency of 21.2 kHz, a magnetic flux density as high as 108 fT at a distance of 100 m is produced from a single ME-MLTx. In addition, ME-MLTx performs a decreased mechanical quality factor (Q m) less than 40.65, and, thus, a broadened bandwidth of 500 Hz is generated. Finally, a communication link transmitting binary American Standard Code for Information Interchange-coded message is built, which allows for an error-free communication with a distance of 18 m and a data rate of 300 bit/s in the presence of heavy environment noise. The communication distance can be further estimated over 100 m when using a femtotesla-class-inductive magnetic field receiver. The obtained results are believed to bring ME antennas one step closer to being applicable in very-low-frequency communications.

3.
Front Immunol ; 14: 1138524, 2023.
Article in English | MEDLINE | ID: mdl-37234166

ABSTRACT

Background: Forkhead box M1 (FOXM1) is a member of the Forkhead box (Fox) transcription factor family. It regulates cell mitosis, cell proliferation, and genome stability. However, the relationship between the expression of FOXM1 and the levels of m6a modification, immune infiltration, glycolysis, and ketone body metabolism in HCC has yet to be fully elucidated. Methods: Transcriptome and somatic mutation profiles of HCC were downloaded from the TCGA database. Somatic mutations were analyzed by maftools R package and visualized in oncoplots. GO, KEGG and GSEA function enrichment was performed on FOXM1 co-expression using R. We used Cox regression and machine learning algorithms (CIBERSORT, LASSO, random forest, and SVM-RFE) to study the prognostic value of FOXM1 and immune infiltrating characteristic immune cells in HCC. The relationship between FOXM1 and m6A modification, glycolysis, and ketone body metabolism were analyzed by RNA-seq and CHIP-seq. The competing endogenous RNA (ceRNA) network construction relies on the multiMiR R package, ENCORI, and miRNET platforms. Results: FOXM1 is highly expressed in HCC and is associated with a poorer prognosis. At the same time, the expression level of FOXM1 is significantly related to the T, N, and stage. Subsequently, based on the machine learning strategies, we found that the infiltration level of T follicular helper cells (Tfh) was a risk factor affecting the prognosis of HCC patients. The high infiltration of Tfh was significantly related to the poor overall survival rate of HCC. Besides, the CHIP-seq demonstrated that FOXM1 regulates m6a modification by binding to the promoter of IGF2BP3 and affects the glycolytic process by initiating the transcription of HK2 and PKM in HCC. A ceRNA network was successfully obtained, including FOXM1 - has-miR-125-5p - DANCR/MIR4435-2HG ceRNA network related to the prognosis of HCC. Conclusion: Our study implicates that the aberrant infiltration of Tfh associated with FOXM1 is a crucial prognostic factor for HCC patients. FOXM1 regulates genes related to m6a modification and glycolysis at the transcriptional level. Furthermore, the specific ceRNA network can be used as a potential therapeutic target for HCC.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Algorithms , Carcinoma, Hepatocellular/genetics , Forkhead Box Protein M1/genetics , Forkhead Transcription Factors/genetics , Glycolysis/genetics , Ketones , Liver Neoplasms/genetics
4.
Polymers (Basel) ; 15(10)2023 May 15.
Article in English | MEDLINE | ID: mdl-37242890

ABSTRACT

Epoxy resin (EP), as a kind of dielectric polymer, exhibits the advantages of low-curing shrinkage, high-insulating properties, and good thermal/chemical stability, which is widely used in electronic and electrical industry. However, the complicated preparation process of EP has limited their practical applications for energy storage. In this manuscript, bisphenol F epoxy resin (EPF) was successfully fabricated into polymer films with a thickness of 10~15 µm by a facile hot-pressing method. It was found that the curing degree of EPF was significantly affected by changing the ratio of EP monomer/curing agent, which led to the improvement in breakdown strength and energy storage performance. In particular, a high discharged energy density (Ud) of 6.5 J·cm-3 and efficiency (η) of 86% under an electric field of 600 MV·m-1 were obtained for the EPF film with an EP monomer/curing agent ratio of 1:1.5 by hot pressing at 130 °C, which indicates that the hot-pressing method could be facilely employed to produce high-quality EP films with excellent energy storage performance for pulse power capacitors.

5.
Adv Healthc Mater ; 11(1): e2101698, 2022 01.
Article in English | MEDLINE | ID: mdl-34549554

ABSTRACT

Bacterial infections have become major threats to public health all over the world. With the emergence of antibiotic resistance, it is urgent to develop novel antimicrobial materials to efficiently overcome drug resistance with high bactericidal activity. In this work, UiO-66-NH-CO-MoS2 nanocomposites (UNMS NCs) are constructed through the amidation reaction. The UNMS NCs are positively charged which is beneficial for capturing and restricting bacteria. Significantly, UNMS NCs possess a synergistic bactericidal efficiency based on near-infrared irradiation (808 nm) regulated combination of photothermal, photodynamic, and peroxidase-like enzymatic activities. Both the photodynamic property and nanozymatic activity of UNMS NCs can lead to the generation of reactive oxygen species. The UNMS NCs show high catalytic activity in a wide pH range and exhibit excellent antibacterial ability against ampicillin-resistant Escherichia coli and methicillin-resistant Staphylococcus aureus with negligible cytotoxicity. Interestingly, due to the 808 nm irradiation-induced hyperthermia in the presence of UNMS NCs, the glutathione oxidation process can be accelerated, resulting in bacterial death more easily. Mice wound models are established to further manifest that UNMS NCs can promote wound healing with good biosafety in living systems.


Subject(s)
Anti-Bacterial Agents , Bacterial Infections , Drug Resistance, Bacterial , Metal-Organic Frameworks , Methicillin-Resistant Staphylococcus aureus , Animals , Anti-Bacterial Agents/pharmacology , Bacterial Infections/drug therapy , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice , Molybdenum , Peroxidase , Peroxidases , Phthalic Acids
6.
Nanomaterials (Basel) ; 11(7)2021 Jun 24.
Article in English | MEDLINE | ID: mdl-34202614

ABSTRACT

For conventional synthesis of Ni(OH)2/graphene hybrids, oxygen-containing functional groups should be firstly introduced on graphene to serve as active sites for the anchoring of Ni(OH)2. In this work, a method for growing Ni(OH)2 nanosheets on multilayer graphene (MLG) with molecular connection is developed which does not need any pre-activation treatments. Moreover, Ni(OH)2 nanosheets can be controlled to stand or lie on the surface of MLG. The prepared hybrids were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The growth processes are suggested according to their morphologies at different growth stages. The enhanced electrochemical performances as supercapacitor electrode materials were confirmed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. Ni(OH)2 nanosheets standing and lying on MLG show specific capacities of 204.4 mAh g-1 and 131.7 mAh g-1, respectively, at 1 A g-1 based on the total mass of the hybrids and 81.5% and 92.8% capacity retention at a high current density of 10 A g-1, respectively. Hybrid supercapacitors with as-prepared hybrids as cathodes and activated carbon as anode were fabricated and tested.

7.
Cell Death Dis ; 12(6): 572, 2021 06 03.
Article in English | MEDLINE | ID: mdl-34083513

ABSTRACT

Kidney fibrosis is a hallmark of chronic kidney disease (CKD) progression that is caused by tubular injury and dysregulated lipid metabolism. Genetic abolition fatty acid-binding protein 4 (FABP4), a key lipid transporter, has been reported to suppress kidney interstitial fibrosis. However, the role and underlying mechanism of chemical inhibition of FABP4 in fibrotic kidney have not been well-documented. Here, we examined preemptive the effect of a FABP4 inhibitor, BMS309403, on lipid metabolism of tubular epithelial cells (TECs) and progression of kidney fibrosis. The expression of FABP4 was significantly elevated, concomitated with the accumulation of lipid droplets in TECs during kidney fibrosis. Treatment with BMS309403 alleviated lipid deposition of TECs, as well as interstitial fibrotic responses both in unilateral ureteral obstruction (UUO)-engaged mice and TGF-ß-induced TECs. Moreover, BMS309403 administration enhanced fatty acid oxidation (FAO) in TECs by regulating peroxisome proliferator-activated receptor γ (PPARγ) and restoring FAO-related enzyme activities; In addition, BMS309403 markedly reduced cell lipotoxicity, such as endoplasmic reticulum (ER) stress and apoptosis in fibrotic kidney. Taken together, our results suggest that preemptive pharmacological inhibition of FABP4 by BMS309403 rebalances abnormal lipid metabolism in TECs and attenuates the progression of kidney fibrosis, thus may hold therapeutic potential for the treatment of fibrotic kidney diseases.


Subject(s)
Fatty Acid-Binding Proteins/metabolism , Kidney/pathology , Lipid Metabolism/physiology , Renal Insufficiency, Chronic/genetics , Animals , Fibrosis , Male , Mice
8.
J Gerontol A Biol Sci Med Sci ; 76(3): 456-462, 2021 02 25.
Article in English | MEDLINE | ID: mdl-32766817

ABSTRACT

BACKGROUND: The epidemic of COVID-19 presents a special threat to older adults. However, information on kidney damage in older patients with COVID-19 is limited. Acute kidney injury (AKI) is common in hospitalized adults and associated with poor prognosis. We sought to explore the association between AKI and mortality in older patients with COVID-19. METHODS: We conducted a retrospective, observational cohort study in a large tertiary care university hospital in Wuhan, China. All consecutive inpatients older than 65 years with COVID-19 were enrolled in this cohort. Demographic data, laboratory values, comorbidities, treatments, and clinical outcomes were all collected. Data were compared between patients with AKI and without AKI. The association between AKI and mortality was analyzed. RESULTS: Of 1764 in-hospital patients, 882 older adult cases were included in this cohort. The median age was 71 years (interquartile range: 68-77), 440 (49.9%) were men. The most presented comorbidity was cardiovascular diseases (58.2%), followed by diabetes (31.4%). Of 882 older patients, 115 (13%) developed AKI and 128 (14.5%) died. Patients with AKI had higher mortality than those without AKI (68 [59.1%] vs 60 [7.8%]; p < .001). Multivariable Cox regression analysis showed that increasing odds of in-hospital mortality are associated with higher interleukin-6 on admission, myocardial injury, and AKI. CONCLUSIONS: Acute kidney injury is not an uncommon complication in older patients with COVID-19 but is associated with a high risk of death. Physicians should be aware of the risk of AKI in older patients with COVID-19.


Subject(s)
Acute Kidney Injury/mortality , COVID-19/mortality , Hospital Mortality , Pneumonia, Viral/mortality , Aged , Aged, 80 and over , COVID-19/epidemiology , China/epidemiology , Female , Hospitalization , Humans , Male , Pandemics , Pneumonia, Viral/virology , Prognosis , Retrospective Studies , SARS-CoV-2
9.
Cell Death Dis ; 11(11): 994, 2020 11 20.
Article in English | MEDLINE | ID: mdl-33219209

ABSTRACT

Following a chronic insult, renal tubular epithelial cells (TECs) contribute to the development of kidney fibrosis through dysregulated lipid metabolism that lead to lipid accumulation and lipotoxicity. Intracellular lipid metabolism is tightly controlled by fatty acids (FAs) uptake, oxidation, lipogenesis, and lipolysis. Although it is widely accepted that impaired fatty acids oxidation (FAO) play a crucial role in renal fibrosis progression, other lipid metabolic pathways, especially FAs uptake, has not been investigated in fibrotic kidney. In this study, we aim to explore the potential mechanically role of FAs transporter in the pathogenesis of renal fibrosis. In the present study, the unbiased gene expression studies showed that fatty acid transporter 2 (FATP2) was one of the predominant expressed FAs transport in TECs and its expression was tightly associated with the decline of renal function. Treatment of unilateral ureteral obstruction (UUO) kidneys and TGF-ß induced TECs with FATP2 inhibitor (FATP2i) lipofermata restored the FAO activities and alleviated fibrotic responses both in vivo and in vitro. Moreover, the expression of profibrotic cytokines including TGF-ß, connective tissue growth factor (CTGF), fibroblast growth factor (FGF), and platelet-derived growth factor subunit B (PDGFB) were all decreased in FATP2i-treated UUO kidneys. Mechanically, FATP2i can effectively attenuate cell apoptosis and endoplasmic reticulum (ER) stress induced by TGF-ß treatment in cultured TECs. Taking together, these findings reveal that FATP2 elicits a profibrotic response to renal interstitial fibrosis by inducing lipid metabolic reprogramming including abnormal FAs uptake and defective FAO in TECs.


Subject(s)
Coenzyme A Ligases/metabolism , Kidney/metabolism , Kidney/pathology , Animals , Cell Line , Fatty Acid Transport Proteins/metabolism , Fibrosis/metabolism , Fibrosis/pathology , Humans , Kidney Tubules/metabolism , Kidney Tubules/pathology , Lipid Metabolism , Male , Mice , Mice, Inbred C57BL
10.
J Int Med Res ; 48(10): 300060520954713, 2020 Oct.
Article in English | MEDLINE | ID: mdl-33100076

ABSTRACT

More than 150 cases of Fanconi syndrome (FS) or hypophosphatemia osteomalacia induced by low-dose adefovir dipivoxil (ADV) have been reported since 2002, when ADV was introduced for the long-term treatment of hepatitis B virus (HBV) infection. Because the life expectancy of HBV-infected individuals has increased, the adverse effects of long-term treatment with antiviral therapies are increasingly observed, and nephrotoxicity is one of the most severe adverse effects of ADV. Therefore, the number of cases may be far higher than reported. Moreover, ADV-induced FS is often misdiagnosed or diagnosed long after it first develops. ADV-induced FS may seriously decrease patient quality of life and lead to bone fractures and even disability. Although progress has been made in the identification of biomarkers and treatments, few systematic clinical guidelines or clinical reviews for FS induced by ADV have been reported. In this study, we highlighted the recent progress toward understanding of FS induced by ADV, described a clinical case, and summarized the primary characteristics and laboratory findings of this disease.


Subject(s)
Fanconi Syndrome , Hepatitis B, Chronic , Adenine/analogs & derivatives , Antiviral Agents/adverse effects , Fanconi Syndrome/chemically induced , Fanconi Syndrome/diagnosis , Fanconi Syndrome/drug therapy , Hepatitis B virus , Humans , Organophosphonates , Quality of Life
11.
ACS Appl Mater Interfaces ; 12(39): 43942-43949, 2020 Sep 30.
Article in English | MEDLINE | ID: mdl-32885648

ABSTRACT

Ceramic dielectrics are reported with superior energy storage performance for applications, such as power electronics in electrical vehicles. A recoverable energy density (Wrec) of ∼4.55 J cm-3 with η ∼ 90% is achieved in lead-free relaxor BaTiO3-0.06Bi2/3(Mg1/3Nb2/3)O3 ceramics at ∼520 kV cm-1. These ceramics may be co-fired with Ag/Pd, which constitutes a major step forward toward their potential use in the fabrication of commercial multilayer ceramic capacitors. Compared to stoichiometric Bi(Mg2/3Nb1/3)O3-doped BaTiO3 (BT), A-site deficient Bi2/3(Mg1/3Nb2/3)O3 reduces the electrical heterogeneity of BT. Bulk conductivity differs from the grain boundary only by 1 order of magnitude which, coupled with a smaller volume fraction of conducting cores due to enhanced diffusion of the dopant via A-site vacancies in the A-site sublattice, results in higher breakdown strength under an electric field. This strategy can be employed to develop new dielectrics with improved energy storage performance.

12.
Nutrition ; 78: 110930, 2020 10.
Article in English | MEDLINE | ID: mdl-32854020

ABSTRACT

OBJECTIVES: High-risk patients ≥65 y of age with coronavirus disease 2019 (COVID-19) tended to have lower serum prealbumin concentrations. The aim of this study was to investigate the association of prealbumin at baseline on COVID-19-related mortality in elderly patients (≥65 y of age). METHODS: We non-selectively and consecutively collected participants from Tongji Hospital in Wuhan from January 17 to February 17, 2020. Univariate and multivariate logistic regression models were employed to evaluate the correlation between prealbumin and in-hospital outcomes (in-hospital mortality, admission to the intensive care unit [ICU], and mechanical ventilation) in elderly patients with COVID-19. Linear trend was performed by entering the median value of each category of prealbumin tertile as a continuous variable and was visually confirmed by using generalized additive models. Interaction and stratified analyses were conducted as well. RESULTS: We included 446 elderly patients with COVID-19 in the final analyses. In-hospital mortality was 14.79%. Of the 446 patients, 15.47% were admitted to the ICU and 21.3% required mechanical ventilation. Compared with patients in the highest tertile, the prealbumin of patients in the lowest tertile had a 19.09-fold higher risk for death [odds ratio (OR), 20.09; 95% confidence interval (CI), 3.62-111.64; P = 0.0006], 25.39-fold higher risk for ICU admission (OR, 26.39; 95% CI, 4.04-172.39; P = 0.0006), and 1.8-fold higher risk for mechanical ventilation (OR, 2.8; 95% CI, 1.15-6.78; P = 0.0227) after adjustment for potential confounders. There was a linear trend correlation between serum prealbumin concentration and risk for in-hospital mortality, ICU admission, and mechanical ventilation in elderly patients with COVID-19 infection. CONCLUSION: Prealbumin is an independent risk factor of in-hospital mortality for elderly patients with COVID-19. Assessment of prealbumin may help identify high-risk individuals ≥65 y of age with COVID-19.


Subject(s)
Betacoronavirus , Coronavirus Infections/blood , Coronavirus Infections/mortality , Hospital Mortality , Pneumonia, Viral/blood , Pneumonia, Viral/mortality , Prealbumin/analysis , Aged , Biomarkers/blood , COVID-19 , China/epidemiology , Female , Humans , Intensive Care Units/statistics & numerical data , Logistic Models , Male , Multivariate Analysis , Odds Ratio , Pandemics , Respiration, Artificial/statistics & numerical data , Risk Assessment , Risk Factors , SARS-CoV-2
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 240: 118543, 2020 Oct 15.
Article in English | MEDLINE | ID: mdl-32526394

ABSTRACT

Detecting cancers through testing biological fluids, namely, "liquid biopsy", is noninvasive and shows great promise in cancer diagnosis, surveillance and screening. Many metabolites that may reflect cancer specificity are concentrated in and excreted through urine. In this study, urine samples were collected from healthy subjects and patients with bladder or prostate cancer. By using surface-enhanced Raman spectroscopy (SERS) with silver nanoparticles, urine sample spectra from 500-1800 cm-1 were obtained. The spectra were classified by principal component analysis and linear discriminant analysis (PCA-LDA). The results showed that the classification accuracy of the model for healthy individuals, bladder cancer patients and prostate cancer patients was 91.9%, and the classification accuracy of the test set was 89%, which indicated that SERS combined with the PCA-LDA diagnostic algorithm could be used as a classification and diagnostic tool to detect and distinguish bladder cancer and prostate cancer through testing urine.


Subject(s)
Metal Nanoparticles , Neoplasms , Discriminant Analysis , Humans , Male , Principal Component Analysis , Silver , Spectrum Analysis, Raman
14.
J Am Acad Dermatol ; 81(5): 1176-1180, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31255749

ABSTRACT

BACKGROUND: Artificial intelligence methods for the classification of melanoma have been studied extensively. However, few studies compare these methods under the same standards. OBJECTIVE: To seek the best artificial intelligence method for diagnosis of melanoma. METHODS: The contrast test used 2200 dermoscopic images. Image segmentations, feature extractions, and classifications were performed in sequence for evaluation of traditional machine learning algorithms. The recent popular convolutional neural network frameworks were used for transfer learning training classification. RESULTS: The region growing algorithm has the best segmentation performance, with an intersection over union of 70.06% and a false-positive rate of 17.67%. Classification performance was better with logistic regression, with a sensitivity of 76.36% and a specificity of 87.04%. The Inception V3 model (Google, Mountain View, CA) worked best in deep learning algorithms: the accuracy was 93.74%, the sensitivity was 94.36%, and the specificity was 85.64%. LIMITATIONS: There was no division in the severity of melanoma samples used in this experiment. The data set was relatively small for deep learning. CONCLUSION: The performance of traditional machine learning is satisfactory for the small data set of melanoma dermoscopic images, and the potential for deep learning in the future big data era is enormous.


Subject(s)
Artificial Intelligence , Melanoma/pathology , Skin Neoplasms/pathology , Dermoscopy , Humans , Melanoma/classification , Reproducibility of Results , Retrospective Studies , Sensitivity and Specificity , Skin Neoplasms/classification
15.
Materials (Basel) ; 12(9)2019 Apr 27.
Article in English | MEDLINE | ID: mdl-31035538

ABSTRACT

Dense (Bi0.95Li0.05)(V0.9Mo0.1)O4-Na2Mo2O7 (100-x) wt.% (Bi0.95Li0.05)(V0.9Mo0.1)O4 (BLVMO)-x wt.% Na2Mo2O7 (NMO) composite ceramics were successfully fabricated through cold sintering at 150 °C under at 200 MPa for 30 min. X-ray diffraction, back-scattered scanning electron microscopy, and Raman spectroscopy not only corroborated the coexistence of BLVMO and NMO phases in all samples, but also the absence of parasitic phases and interdiffusion. With increasing NMO concentration, the relative pemittivity (εr) and the Temperature Coefficient of resonant Frequency (TCF) decreased, whereas the Microwave Quality Factor (Qf) increased. Near-zero TCF was measured for BLVMO-20wt.%NMO composites which exhibited εr ~ 40 and Qf ~ 4000 GHz. Finally, a dielectric Graded Radial INdex (GRIN) lens was simulated using the range of εr in the BLVMO-NMO system, which predicted a 70% aperture efficiency at 26 GHz, ideal for 5G applications.

16.
Nanoscale Res Lett ; 13(1): 343, 2018 Oct 29.
Article in English | MEDLINE | ID: mdl-30374742

ABSTRACT

The lattice stability and phonon response of Ti3C2Tx MXene at high pressure are important for understanding its mechanical and thermal properties fully. Here, we use in situ high hydrostatic pressure X-ray diffraction (XRD) and Raman spectroscopy to study the lattice deformation and phonon behavior of Ti3C2Tx MXene. XRD spectra indicate that no phase transformation occurs up to the pressure of 26.7 GPa. The elastic constant along a lattice parameter was calculated to be 378 GPa. In the Raman spectra obtained at high-pressure, the out-of-plane phonon modes (A1g at ~ 210, ~ 504, and ~ 711 cm-1) exhibit monotonic blueshifts with increasing pressure. The Grüneisen parameters of these three modes were calculated to be 1.08, 1.16, and 0.29, respectively. These results enrich the basic property data of Ti3C2Tx MXene and would benefit the further understanding of this novel material.

17.
Chem Commun (Camb) ; 54(7): 743-746, 2018 Jan 18.
Article in English | MEDLINE | ID: mdl-29308495

ABSTRACT

A nonstoichiometric process by modulating the W/Se atomic ratio was employed to tune the excitonic PL band of monolayer WSe2 from 810 nm to 690 nm. DFT calculations indicate that Se-rich conditions reduce the band gap, while Se-deficient conditions facilitate the increasing band gap and decreasing excitionic binding energy, which finally induces such broadband tuning of the PL band.

18.
Chemphyschem ; 16(18): 3784-9, 2015 Dec 21.
Article in English | MEDLINE | ID: mdl-26436998

ABSTRACT

Conventional luminescent color coding is limited by spectral overlap and the interference of background fluorescence, thus restricting the number of distinguishable identities that can be used in practice. Here, we demonstrate the possibility of generating diverse time-domain codes, specially designed for a single emission band, using lanthanide-doped upconversion nanocrystals. Based on the knowledge of concentration quenching, the upconversion luminescence kinetics of KYb2 F7 : Ho(3+) nanocrystals can be precisely controlled by modifying the dopant concentration of Ho(3+) ions, resulting in a tunable emission lifetime from 75.8 to 1944.5 µs, which suggests the practicality of these time-domain codes for optical multiplexing.


Subject(s)
Holmium/chemistry , Nanoparticles , Spectrum Analysis/methods , Microscopy, Electron, Transmission
19.
Chem Commun (Camb) ; 51(41): 8584-7, 2015 May 21.
Article in English | MEDLINE | ID: mdl-25853927

ABSTRACT

We demonstrate, in great detail, a completely waterless synthesis route to produce highly crystalline epitaxial thin films of TiO2-B and its more stable variant CaTi5O11, using pulsed laser deposition (PLD).

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