Showing papers by "Wei Jin published in 2016"

Recent Advances in the Synthesis of Layered, Double‐Hydroxide‐Based Materials and Their Applications in Hydrogen and Oxygen Evolution

Abstract: Layered double hydroxides (LDHs) consist of brucite-like layers containing hydroxides of two or more different kinds of metal cations. These positively charged layers are neutralized by exchangeable anions in the interlayer galleries. LDH-based materials have substantial potential in efficient energy (e.g., H-2, O-2) generation. Over the last few decades, tremendous progress has been made toward developing LDH-based materials for H-2 and O-2 evolution, for which the performance of LDH-based materials is closely related to the synthesis method. This minireview initially outlines the recent advances in the synthesis of LDH-based materials. The advantages and challenges of the protocols in tuning the properties of the material are also discussed and highlighted. The application section concentrates on the most recent progress in photocatalytic H-2 generation and photocatalytic and electrocatalytic O-2 evolution. By taking advantage of the flexible tunability and uniform distribution of metal cations in the brucite-like layers or the intercalated anions in the interlayer space, LDH-based materials exhibit attractive properties in the generation of H-2 and O-2 with advantages such as improved light absorption, enhanced charge separation, better electron transfer, promoted electrode reaction kinetics, and high durability.

Mode converters based on cascaded long-period waveguide gratings.

Abstract: We propose a mode-conversion platform based on cascaded long-period waveguide gratings. We demonstrate two specific devices by cascading a surface-corrugated grating and a sidewall-corrugated grating. One device allows conversion among the LP01, LP11b, and LP11a modes in a cyclic manner. The maximum conversion efficiency of a typical experimental device fabricated with polymer materials is about 94% at 1540 nm. The other device allows conversion between the LP01 and LP21a modes. The maximum conversion efficiency of a typical experimental device is estimated to be higher than 90% at 1550 nm. The performance of both devices is polarization-insensitive. The proposed platform could be developed into various mode converters for mode-division-multiplexing systems and other mode-sensitive applications.

SSBP1 Suppresses TGFβ-Driven Epithelial-to-Mesenchymal Transition and Metastasis in Triple-Negative Breast Cancer by Regulating Mitochondrial Retrograde Signaling

Abstract: Triple-negative breast cancer (TNBC) is a highly aggressive tumor subtype lacking effective prognostic indicators or therapeutic targets. Mitochondrial function is dysregulated frequently in cancer cells to allow for adaptation to a harsh tumor microenvironment. Targeting mitochondrial biogenesis and bioenergetics is, therefore, an attractive therapeutic strategy. In this study, we performed quantitative proteomic analyses in human parental and metastatic breast cancer cell lines to identify mitochondrial proteins involved in TNBC metastasis. We found that single-strand DNA-binding protein 1 (SSBP1) was downregulated in highly metastatic breast cancer cells. Moreover, SSBP1 downregulation promoted TNBC cell metastasis in vitro and in vivo. Mechanistically, SSBP1 loss decreased mitochondrial DNA copy number, thereby potentiating calcineurin-mediated mitochondrial retrograde signaling that induced c-Rel/p50 nuclear localization, activated TGFβ promoter activity, and TGFβ-driven epithelial-to-mesenchymal transition. Low SSBP1 expression correlated with tumor progression and poor prognosis in patients. Collectively, our findings identified SSBP1 as a novel metastasis suppressor and elucidated the mechanisms by which dysregulated mitochondrial signaling contributes to metastatic potential, providing potential new prognostic indicators for patients with TNBC.

Hollow-core fiber Fabry–Perot photothermal gas sensor

Abstract: A highly sensitive, compact, and low-cost trace gas sensor based on photothermal effect in a hollow-core fiber Fabry–Perot interferometer (FPI) is described. The Fabry–Perot sensor is fabricated by splicing a piece of hollow-core photonic bandgap fiber (HC-PBF) to single-mode fiber pigtails at both ends. The absorption of a pump beam in the hollow core results in phase modulation of probe beam, which is detected by the FPI. Experiments with a 2 cm long HC-PBF with femtosecond laser drilled side-holes demonstrated a response time of less than 19 s and noise equivalent concentration (NEC) of 440 parts-per-billion (ppb) using a 1 s lock-in time constant, and the NEC goes down to 117 ppb (2.7×10−7 in absorbance) by using 77 s averaging time.

Pulsed photothermal interferometry for spectroscopic gas detection with hollow-core optical fibre.

Abstract: Gas detection with hollow-core photonic bandgap fibre (HC-PBF) and pulsed photothermal (PT) interferometry spectroscopy are studied theoretically and experimentally. A theoretical model is developed and used to compute the gas-absorption-induced temperature and phase modulation in a HC-PBF filled with low-concentration of C2H2 in nitrogen. The PT phase modulation dynamics for different pulse duration, peak power and energy of pump beam are numerically modelled, which are supported by the experimental results obtained around the P(9) absorption line of C2H2 at 1530.371 nm. Thermal conduction is identified as the main process responsible for the phase modulation dynamics. For a constant peak pump power level, the phase modulation is found to increase with pulse duration up to ~1.2 μs, while it increases with decreasing pulse duration for a constant pulse energy. It is theoretically possible to achieve ppb level detection of C2H2 with ~1 m length HC-PBF and a pump beam with ~10 ns pulse duration and ~100 nJ pulse energy.

IL-17C is required for lethal inflammation during systemic fungal infection.

Abstract: Within the interleukin-17 (IL-17) family of cytokines, IL-17A is known to be critical in the host defense against fungal infections; however, the function of the other IL-17 family members in anti-fungal immunity remains largely unknown. Here, we show that IL-17C expression was highly induced in kidney epithelial cells after fungal infection. Mice that lacked IL-17C exhibited increased survival and attenuated kidney tissue damage, although they had similar fungal loads. IL-17C deficiency resulted in decreased pro-inflammatory cytokine expression compared with wild-type control mice. Additionally, IL-17C directly acted on renal epithelial cells in vitro to promote pro-inflammatory cytokine production. Taken together, our data demonstrate that IL-17C is a critical factor that potentiates inflammatory responses and causes host injury during fungal infection.

Electro-optic mode switch based on lithium-niobate Mach-Zehnder interferometer.

Abstract: We propose an electro-optic mode switch based on an optical waveguide Mach–Zehnder interferometer fabricated with x-cut lithium niobate by the annealed proton exchange process. The device can switch between the fundamental mode and the higher-order mode with a low driving voltage. Our typical fabricated device, which has a total length of ∼24 mm, shows a mode extinction ratio of ∼35 dB and a 20-dB bandwidth of ∼12 nm at the wavelength 1552 nm, when driven at a voltage of 1.7 V at 26°C. High performance can be obtained at any wavelength in the C+L band with a driving voltage varying by no more than 3 V. The proposed mode switch is easy to fabricate and could find applications in reconfigurable mode-division-multiplexing systems.

Tuning α-Fe2O3 nanotube arrays for the oxygen reduction reaction in alkaline media

Abstract: The oxygen reduction reaction plays a crucial role in alkaline fuel cells. Herein, an α-Fe2O3 nanotube array material was fabricated via a facile two-step electrochemical anodization method and employed as an efficient ORR catalyst in alkaline media. Due to its highly ordered open top architecture, the α-Fe2O3 nanotube array electrode exhibits excellent ORR catalytic activity with an onset potential of −0.39 V (vs. Hg/HgO) and high current density of 6.95 mA cm−2. Results show that the ORR exhibits quasi-reversible diffusion-controlled reaction characteristics and a well-defined four electron pathway. Moreover, as the crystalline structure transforms from α-Fe2O3 to Fe3O4 or as the alkaline concentration increases, the ORR activity is disturbed and the electron transfer number decreases. The as-prepared electrodes possess favorable alkaline tolerance as indicated from their chronoamperometric curves and Raman spectra. Accordingly, this novel α-Fe2O3 nanotube array material can be employed as efficient and low cost non-noble metal electrodes for electrochemical energy applications.

Defluoridation by rice spike-like akaganeite anchored graphene oxide

Abstract: Due to intake of excessive fluoride in drinking water, endemic fluorosis, the most widely distributed endemic diseases has caused worldwide attention. In this study, akaganeite anchored graphene oxide (β-FeOOH@GO) nanocomposites were synthesized by in situ forced hydrolysis of ferric chloride in presence of graphene oxide under facile condition. β-FeOOH@GO was characterized and evaluated as a new potential carbon sorbent for defluoridation in environmental application. The application pH, adsorption capacity, adsorption kinetic and anti-interference ability in defluoridation with β-FeOOH@GO was described. On the basis of Fourier transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analysis, defluoridation mechanism involving the ion-exchange with chloride anions bearing in β-FeOOH@GO is indicated at molecular level from a new perspective way. It is a good supplement to classical hydroxyl replacement mechanism. It would be useful for the improvement of adsorption capacity and kinetics through designing facile anions-exchange adsorbents.

Facile Synthesis of Mesoporous Manganese–Iron Nanorod Arrays Efficient for Water Oxidation

Abstract: Water splitting for the production of oxygen is a promising strategy to advance many renewable energy conversion systems, while the cost-effective and green synthesis of a high-performance catalyst composed of earth-abundant elements is still a big challenge. A facile and green synthesis of nonprecious MnFe2O4 nanorod arrays at low temperature is developed here, where the as-obtained hierarchical MnFe2O4 nanorod arrays exhibit mesoporous structure, large surface area and nice dispersion. These fabricated mesoporous MnFe2O4 nanorod arrays are efficient for water oxidation in 0.1 M NaOH, giving rise to a low overpotential of ∼0.315 VRHE at 10.0 mA cm–2, a high current density (10 times higher than that of commercial 20 wt % Pt/C catalyst at 1.80 VRHE) and largely enhanced stability. These performances are much superior to previously reported electro-oxidation catalysts as well as the state-of-the-art RuO2 and precious 20 wt % Pt/C catalysts. In particular, this preparation method of MnFe2O4 nanorods is amen...

Electrochemical Cr(III) Oxidation and Mobilization by In Situ Generated Reactive Oxygen Species in Alkaline Solution

Abstract: A novel electrochemical chromium oxidation strategy by in situ electro-generated reactive oxygen species was developed in this study. Activated multi-walled carbon nanotubesmodified electrode was employed to produce H2O2 via two-electron-pathway oxygen reduction reaction with onset potential of -0.06 V (vs Hg/HgO) and peak current density of 1.54 mA . cm(-2). The H2O2 formation was confirmed by selective luminescent probes with UV-vis spectroscopy, and the Cr(III) can be efficiently oxidized by the as formed H2O2. Interestingly, center dot OH can also be obtained by the Cr(III)-induced Fenton-like reaction, and offer further oxidative stress to enhance the Cr(III) oxidation. Consequently, a significantly enhanced Cr(III) conversion of 98.5 +/- 1.0% was achieved in this indirect oxidation as compared to 29.8 +/- 1.3% in the corresponding direct electrochemical oxidation. Besides, indirect pathway exhibited a considerable improvement for the Cr(III) oligomers oxidation (from 17.6 +/- 1.0% to 93.5 +/- 1.5%), indicating a potential solution to overcome the polymerization bottleneck of Cr(III) oxidation. Moreover, the electrolysis current well maintained the original value after stability test, suggesting favorable alkaline tolerance. The proposed method provided a cleaner approach for Cr(III) oxidative mobilization in alkaline media, and new insight on the redox cycle of electro-generated reactive oxygen species. (C) 2016 The Electrochemical Society. All rights reserved.

An Overview on Fast Pyrolysis of the Main Constituents in Lignocellulosic Biomass to Valued‐Added Chemicals: Structures, Pathways and Interactions

Abstract: Considering the huge demand of energy for social economic development and deterioration of environment due to extensive utilization of fossil fuels, green and renewable energy sources are standing in the centre for alleviating the mentioned pressure and diversifying the global energy supply. “Pyrolysis”, as one of the promising thermo-chemical conversion technologies, could convert biomass to value-added chemicals and fuels in forms of solid, liquid and gas. Fast pyrolysis of the main constituents in biomass (polysaccharides and lignin averagely accounting for 90 wt%), involving the yield of liquid/solid/gas products, distribution of prominent oxygenate compounds, their formation pathways associated with the chemical structure of highly polymerized macromolecules, would be vigorously discussed in this review work, helping to improve the understanding of pyrolytic behavior of biomass, optimize the thermal conversion process and so on. Meanwhile, the interaction among the components during pyrolytic process was evidenced and briefly overviewed, in order to shorten the distance between the pyrolysis of biomass and pyrolytic behavior of its main components and design the new-concept co-pyrolysis process for promoting the production of oxygenated compounds. The challenges and wayforward in the field are addressed in estimating the formation priority of specific oxygenate compounds and developing new technology for producing the value-added compounds (chemicals) in high yields.

Loss of TIM50 suppresses proliferation and induces apoptosis in breast cancer.

Abstract: TIM50 is an essential component of TIM23 complex and involved in protein translocating into the inner mitochondrial membrane. Here, we found that TIM50 was increased in breast cancer cells by SILAC. However, its biological functions and molecular mechanisms in breast cancer are poorly understood. To gain insight into the functions of TIM50 in breast cancer, we constructed two stably transfected cell lines and examined TIM50 expression in tissue samples. Our data showed that TIM50 expression was increased in breast cancer. The stable suppression of TIM50 expression through lentivirus-mediated shRNA was shown to inhibit the abilities of cancer cell proliferation and induce apoptosis. What is more, depletion of TIM50 could decrease mitochondrial membrane potential, which may be associated with cell viability. Taken together, our findings reveal a new role for TIM50 in regulating cell proliferation and apoptosis through decreasing mitochondrial membrane potential in breast cancer cell and suggest that TIM50 might be a potential target for controlling breast cancer progression.

Measurement of the Adhesion Energy of Pressurized Graphene Diaphragm Using Optical Fiber Fabry–Perot Interference

Abstract: Van der Waals adhesion between graphene and substrate has an important impact on the graphene-based sensor performance. Here, we proposed a simple in situ measurement method for the adhesion energy of the graphene diaphragm suspended on the endface of a ferrule. The interaction between the diaphragm and its substrate created a low finesse Fabry–Perot (FP) interferometer. The analytical relationship between prestress and adhesion energy was modeled on the basis of the initial dip along the edges of the suspended regions. Then, the deflection deformations of pressurized graphene diaphragm were examined using the FP interference technology. The obtained adhesion energies for monolayer and two to five layer graphene membranes on SiO2 conformed exceedingly well to the previously measured results and yielded a cross-correlation coefficient of 0.999 with the latter. Furthermore, an experimental setup for acoustic pressure test was developed to determine the adhesion energies for $\sim 7$ -layer and $\sim 13$ -layer graphene diaphragms with a zirconia substrate to be 0.286 and 0.275 J/ $\text{m}^{2}$ , respectively. The highly consistent experimental data confirmed the accuracy of our method. This method presented in this paper could be further extended for measuring the adhesion energy of other 2-D materials.

High-speed photographic analysis of microwave plasma torch source behaviour

Abstract: Spatiotemporal motion characteristics of the microwave plasma torch (MPT) source were for the first time investigated with a high-speed camera. It was found that the cone shape with a central channel of the Ar MPT, which is beneficial for the introduction of the sample analyzed, is formed by the regular and high-speed rotary motion of the discharge filament(s), and it is also the origin of the unique performance compared with other microwave plasma sources. The rotational frequency of the plasma filament is typically 100 Hz, which is affected by the flow-rates and microwave forward power level. To investigate their relationship, the parametric analysis was used, suggesting that the support gas flow-rate is the major factor, followed by microwave power and the carrier gas flow rate. It was also illustrated that the structural symmetry of the torch is important for the stability of the excitation source. In addition, the excitation process of MgCl2 aerosol in the MPT was preliminary studied on the microscopic time scale. Knowledge of this spatiotemporal behaviour is relevant to studies of the fundamental properties of the MPT and its applications.

All-fiber hydrogen sensor based on stimulated Raman gain spectroscopy with a 1550 nm hollow-core fiber

Abstract: We report a highly sensitive all-fiber hydrogen sensor based on continuous-wave stimulated Raman gain spectroscopy with a hollow-core photonic crystal fiber operating around 1550 nm. A pump-probe configuration is used, in which the frequency difference between the pump and the probe lasers is tuned to the S0(0) transition of para-hydrogen with a Raman shift of 354 cm-1. Preliminary experiments demonstrate a detection limit down to 17 ppm with a 250 s averaging time, and further improvement is possible. The all-fiber configuration operating in the telecommunication wavelength band would enable cost-effective and compact sensors for high sensitivity and high-resolution trace analysis.

Mining Hidden Knowledge from the Counterterrorism Dataset Using Graph-Based Approach

Abstract: Information overloaded is now a matter of fact. These enormous stack of information poses huge potential to discover previously uncharted knowledge. In this paper, we propose a graph based approach integrated with statistical correlation measure to discover latent but valuable information buried under huge corpora. For given two concepts, \(C_i\) and \(C_j\) (e.g. bush and bin ladin), we find the best set of intermediate concepts interlinking them by gleaning across multiple documents. We perform query enrichment on input concepts using Longest Common Substring (LCSubstr) algorithm to enhance the level of granularity. Moreover, we use Kulczynski correlation measure to determine the strength of interdependence between concepts and demote associations with relatively meager statistical significance. Finally, we present our users with ranked paths, along with sentence level evidence to facilitate better interpretation of underlying context. Counterterrorism dataset is used to demonstrate the effectiveness and applicability of our technique.

Adenosine kinase facilitated astrogliosis-induced cortical neuronal death in traumatic brain injury

Abstract: Adenosine kinase (ADK) plays a pivotal role in regulating brain function by regulating adenosine level, and ADK inhibition protects against neuronal damage in cerebral ischemia and epilepsy; however, the effects of ADK in traumatic brain injury (TBI) have not been investigated. For exploring its effects, we generated a blade-induced rat focal brain injury model. Western blot analysis, immunohistochemistry and immunofluorescent staining suggested that ADK was up-regulated after TBI, and it was temporally and spatially associated with astrogliosis. Terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling showed that neuronal apoptosis was paralleled with TBI-induced ADK up-regulation and astrogliosis. For further investigating the role of ADK in astrogliosis-induced neuronal death, primary cultured astrocytes and neurons were utilized, lipopolysaccharide (LPS) was employed to mediate astrogliosis, and condition medium (CM) of reactive astrocytes was used to treat neurons. The results showed that astrocytes increased iNOS expression and secreted pro-inflammatory cytokines after LPS treatment, and CM of reactive astrocytes resulted neuronal death. Additionally, ADK knock-down didn't ameliorate LPS-induced astrocyte proliferation, but it protected against neuronal death by reducing iNOS expression, tumor necrosis factor α and interleukin 1β secretion of reactive astrocytes. Taken together, ADK was associated with astrogliosis after TBI, its inhibition in reactive astrocytes ameliorated astrogliosis-induced neuronal death. Our findings extended the current knowledge on the role of ADK in astrogliosis, and also provided new evidence for the TBI treatment.

Optimization of coagulation–flocculation process for combined sewer overflow wastewater treatment using response surface methodology

Abstract: A different type of combined sewer overflow (CSO) problem in dry weather, with characteristic of high organic pollutant loads and wide variations, has been becoming one of the most serious urban river pollution problems in China. The performance of coagulation–flocculation process in this type of CSO wastewater treatment was investigated in this study, using polyaluminum ferric chloride sulfate (PAFCS) as coagulant. A 23 full-factorial central composite design and response surface methodology were applied to evaluate the effects and interactions for the chemical oxygen demand (COD) removal efficiency by three factors including initial COD concentration, initial suspended solid concentration, and coagulant dosage. A quadratic model was obtained and the analysis of variance results indicated clearly that experimental data could fit the equation well with a R2 of 95.15%. There is a significant interaction between the initial COD concentration and coagulant dosage for COD removal efficiency. The exper...

Support vector machine classification for determination of geographical origin of Chinese ginseng using microwave plasma torch-atomic emission spectrometry

Abstract: The geographical origin of Chinese ginseng is of great concern to customers, since quality varies tremendously with geographical origin. Therefore, accurately distinguishing the region of origin of specific types of ginseng, in order to differentiate the quality, is of great significance. In this paper, MPT-AES integrated with support vector machine (SVM) was proposed and applied to determine and classify the geographical origin of ginseng samples by using the chemical elemental compositions obtained. Specific data sets were extracted and dimensions were reduced through wavelet transformation. A classification model was built, relying on training sets, and then two parameters (c and g) were optimized in the SVM approach. SVM and Gaussian process classification (GPC) models were evaluated entirely on their prediction accuracy for unknown ginseng samples. Under optimized conditions, SVM outperformed GPC with a prediction accuracy of 100%, compared to 97.41%, in distinguishing the geographical origins. SVM also proved valid in the classification of individual types of ginseng with 99.81% accuracy, compared to GPC with 71.67%. These advanced chemometrics worked well for American ginseng identification. This study illustrates that chemometrics, together with the MPT-AES spectrochemical method, is a helpful and innovative technique for identifying and classifying ginseng samples, and is promising for accurate, convenient, automatic and reliable analysis.