A neutron beam monitor based on ceramic gas electron multiplier with high spatial resolution for low flux measurements.

Neutron scattering instruments play an important role in studying the inner structure of materials. A neutron beam monitor is a detector commonly used in a neutron scattering instrument. The detection efficiency for most neutron beam monitors is quite low (10-4-10-6). However, in some experiments with a low neutron flux, such as small angle neutron scattering (SANS) and inelastic neutron scattering experiments, a neutron beam monitor with a higher detection efficiency (∼1% for thermal neutrons) is required to reduce the duration of the experiment. To meet this requirement, a ceramic gas electron multiplier-based neutron beam monitor equipped with a 1 µm 10B4C neutron converter was developed in this study. Its performance was determined both experimentally and in simulations. The detection efficiency in the wavelength range of 1.8-5.5 Å was measured experimentally and was confirmed by the simulation results. An algorithm based on event selection and position reconstruction was developed to improve the spatial resolution to about 1 mm full-width-half-maximum. The wavelength spectrum was measured in beamline 20 (BL20) and agreed well with the results obtained using a commercial monitor. The maximum counting rate was 1.3 MHz. The non-uniformity over the whole 100 × 100 mm2 active area was determined to be 1.4%. Due to the excellent performance of this monitor, it has been used in several neutron instruments, such as the SANS and the High-Energy Direct-Geometry Inelastic Spectrometer instruments in the China spallation neutron source.

Magnetron sputtering system for depositing boron carbide film use as neutron detection.

Boron carbide (B4C) films used as neutron conversion layers were investigated in this paper to replace the traditional 3He detectors due to their shortage. A magnetron sputtering system was developed for depositing large-size B4C films with the 1500 × 400 mm2 uniform-area. B4C films at the micron scale were deposited on aluminum (Al), float glass (SiO2), and silicon (Si) substrates with an inserting adhesion layer. The key characteristics, including surface morphology, thickness nonuniformity, purity, and neutron efficiency of B4C films, were characterized using atomic force microscopy, scanning electron microscopy, grazing incidence x-ray reflectivity, x-ray photoelectron spectroscopy, and neutron radiation metrology. The experimental results indicate that the deposition thickness nonuniformity across a 1500 × 400 mm2 area was better than ±3%. The stoichiometric ratio of boron atoms and carbon atoms (B/C) is 5.18, with 6 at. % O and 0.79 at. % N concentrations. The measured neutron detection efficiency of a 3 µm 10B4C film for 25 meV neutrons was 3.3 ± 0.3(sys)%, which is close to the simulated results (3.4%). The results show that the B4C neutron conversion layer is a promising substitute for 3He for neutron detection in the future.

Effect of Reticulate Unit Spacing on Microstructure and Properties of Biomimetic 7075 Aluminum Alloy by Laser Cladding.

In the context of energy conservation and emission reduction, more and more attention has been paid to the development of lightweight metal materials with both high strength and high toughness. Inspired by the non-smooth surface of natural organisms, a biomimetic surface with various spacing reticulate units of 7075 aluminum alloys was modified by laser cladding. The microstructure, microhardness and tensile properties of the various spacing units with CeO2-SiC-Ni60 were studied. The finer microstructure and the higher microhardness of various spacing units in comparison with that of 7075 aluminum alloys were obtained, no matter the strip-like treated region or the cross-junction region. Moreover, the best combination of strength and toughness of the biomimetic sample with 2.5 mm spacing reticulate unit was discussed. Finally, by combining the microstructure, XRD phase change, thermal gradient effect, thermal expansion coefficient difference and hard phase strengthening mechanism, it was concluded that the 2.5 mm spacing reticulate unit had the best ability to inhibit crack propagation, and the dispersive hard phases of Al3Ni2 and SiC played a major role in stress release of the matrix.

Charging Quantum Batteries via Indefinite Causal Order: Theory and Experiment.

In the standard quantum theory, the causal order of occurrence between events is prescribed, and must be definite. This has been maintained in all conventional scenarios of operation for quantum batteries. In this study we take a step further to allow the charging of quantum batteries in an indefinite causal order (ICO). We propose a nonunitary dynamics-based charging protocol and experimentally investigate this using a photonic quantum switch. Our results demonstrate that both the amount of energy charged and the thermal efficiency can be boosted simultaneously. Moreover, we reveal a counterintuitive effect that a relatively less powerful charger guarantees a charged battery with more energy at a higher efficiency. Through investigation of different charger configurations, we find that ICO protocol can outperform the conventional protocols and gives rise to the anomalous inverse interaction effect. Our findings highlight a fundamental difference between the novelties arising from ICO and other coherently controlled processes, providing new insights into ICO and its potential applications.

Magnetic polyimide nanosheet microspheres for trace analysis of estrogens in aqueous samples by magnetic solid-phase extraction-gas chromatography-mass spectrometry.

Magnetic polyimide nanosheet microspheres (PI-NMs) were used for magnetic solid-phase extraction (MSPE) for the first time. The PI-NMs were modified with magnetic Fe3O4 nanoparticles by chemical coprecipitation to produce the PI-NM/Fe3O4 composite. The prepared composite possessed a nanosheet structure, large specific surface area (71.5 m2/g), high saturation magnetization (19.1 emu/g), large adsorption capacity (≥ 676 ng/mg for selected estrogens), and good extraction stability (> 10 times). Trace estrogens in environmental water and urine samples were extracted by the PI-NM/Fe3O4 composite, desorbed, derivatized, and analyzed by gas chromatography-mass spectrometry (GC-MS). The derivatization, extraction, and desorption conditions were optimized. Extraction equilibrium was achieved within 1 min due to the good dispersibility and large specific surface area of the PI-NM/Fe3O4 composite. Under the optimized conditions, the MSPE/GC-MS method validation results showed wide linearity (0.02-50 µg/L or 0.05-50 µg/L), high determination coefficients (R2 ≥ 0.9983), good intraday and interday precisions (expressed as relative standard deviation, RSDs ≤ 8.2%), and low limits of detection (LODs, 0.001-0.015 µg/L). For the real environmental water and urine samples, the recoveries and RSDs were 77.0-112.5% and 0.1-10.7%, respectively. The performance of the MSPE/GC-MS method proved that the PI-NM/Fe3O4 composite was a good alternative material for the extraction of organic pollutants in aqueous samples.

Porous electrospun microfibers for low flow-resistant solid phase extraction of fluoroquinolones in tap water, egg and milk samples.

In this work, porous electrospun microfibers (PEMFs) were prepared using a polyimide/polyvinylpyrrolidone/polyethylene glycol (PI/PVP/PEG) solution mixture with coaxial ultrasonic water vapor spraying. After removing PVP and PEG by ultrasonic water washing, the PEMFs were successfully demonstrated as adsorbents for solid phase extraction (SPE). Most non-porous electrospun nanofibers are hundreds of nanometers in diameter, with a specific surface area of dozens of square meters per gram. In contrast, the diameter of the as-prepared PEMFs was tuned between 3 and 8 µm, the specific surface area was 76 m2g-1 and the pore size was ca 25 nm. Therefore, the flow resistance of the PEMF-SPE cartridges was similar to those of conventional commercial SPE cartridges, and much lower than those of SPE cartridges packed with electrospun nanofibers. Using the PEMF-SPE cartridges with ultra-performance liquid chromatography-fluorescence detector (UPLC-FLD), five fluoroquinolones (FQs) in tap water, egg and milk samples were extracted and quantified successfully. After optimizing the extraction conditions, FQs in water samples were extracted and eluted with high recoveries of 84.8-114.8%. The inter-batch and intra-batch relative standard deviation (RSD) values for the FQs were in the range of 1.9-9.5% (n=3), and the limits of detection were between 0.0024-0.014 µg L-1. The method was linear in the concentration range of 0.005-10 µg L-1. The reliability of the developed method was validated by analyzing tap water, egg and milk samples, and the recovery values were found to be in the range of 74.8-116.6% under the optimized conditions.

Fully integrated protein absolute quantification platform for analysis of multiple tumor markers in human plasma.

In this study, we developed a fully integrated protein absolute quantification platform for simultaneous analysis of multiple tumor markers in human plasma, by which multiple target proteins (alpha-fetoprotein, prostate-specific antigen, carcino-embryonic antigen and mucin-1) were firstly enriched by aptamers immobilized capillary column using graphene oxide modified polymer microsphere as the separation matrix, and then the eluted target proteins were online denatured, reduced, desalted and digested by our developed fully automated sample treatment device (FAST), finally the resulting peptides were analyzed by parallel reaction monitoring (PRM) on LTQ-orbitrap velos mass spectrometry. Compared to traditional ELISA assay, the platform exhibited significant advantages such as short analysis time, low limit of detection, and ease of automation. Furthermore, our developed platform was also applied in the absolute quantification of tumor markers from clinical human plasma samples, and the results were comparable to those obtained by clinical immunoassay. All the results demonstrated that such a platform could provide a promising tool for achieving high sensitivity, high accuracy, and high throughput detection of disease related protein markers in the routine physical examination and clinical disease diagnosis.

Variations of inorganic ions and dissolved organic matter in different types of peat bogs and its ecological significance.

Peat bogs, which cover only 3% of the global land surface, store about 30% of the global soil carbon (C), and are important carbon pools in terrestrial ecosystems. Dissolved organic matter (DOM) is an important part of carbon cycle in peatland, and also an important participant in biogeo-chemical process of peat. The variation of redox ability of DOM and inorganic ions in surface water, groundwater, and pore water of two sampling peatland (minerotrophic fen, LB; ombrotrophic bog, OS) were analyzed using novel electrochemical method and stable carbon isotope. The results showed that in the LB plot, inorganic elements were rich, and that anaerobic respiration dominated by inorganic electron acceptor was the main process. The redox ability differed across different LB water sources (surface water, groundwater, and pore water), which was mainly affected by the actual redox potentials. Iron and sulfate were generally in reduced state in the profile of pore water. The reaction level and depth of redox active groups of DOM which participated in redox process were influenced by inorganic electron acceptor. In the OS plot, organic matter was extremely rich, and organic electron acceptor contributed significantly in redox process. The redox ability of OS water samples from different sources performed differently, which was also mainly attributed to the actual redox potentials. The redox ability of pore water profile was affected by the chemical composition in peat substance at different depths. Therefore, electron accepting capacities (EAC) and oxidation index (OI) values could be used to identify the redox conditions along the gradient and to indicate the redox state of organic matter in aquatic systems.

Bis(zinc(II)-dipicolylamine)-functionalized sub-2 µm core-shell microspheres for the analysis of N-phosphoproteome.

Protein N-phosphorylation plays a critical role in central metabolism and two/multicomponent signaling of prokaryotes. However, the current enrichment methods for O-phosphopeptides are not preferred for N-phosphopeptides due to the intrinsic lability of P-N bond under acidic conditions. Therefore, the effective N-phosphoproteome analysis remains challenging. Herein, bis(zinc(II)-dipicolylamine)-functionalized sub-2 µm core-shell silica microspheres (SiO2@DpaZn) are tailored for rapid and effective N-phosphopeptides enrichment. Due to the coordination of phosphate groups to Zn(II), N-phosphopeptides can be effectively captured under neutral conditions. Moreover, the method is successfully applied to an E.coli and HeLa N-phosphoproteome study. These results further broaden the range of methods for the discovery of N-phosphoproteins with significant biological functions.

Solution-Processable 2D Polymer/Graphene Oxide Heterostructure for Intrinsic Low-Current Memory Device.

Suppressing the operating current in resistive memory devices is an effective strategy to minimize their power consumption. Herein, we present an intrinsic low-current memory based on two-dimensional (2D) hybrid heterostructures consisting of partly reduced graphene oxide (p-rGO) and conjugated microporous polymer (CMP) with the merits of being solution-processed, large-scale, and well patterned. The device with the heterostructure of p-rGO/CMP sandwiched between highly reduced graphene oxide (h-rGO) and aluminum electrodes exhibited rewritable and nonvolatile memory behavior with an ultralow operating current (∼1 µA) and efficient power consumption (∼2.9 µW). Moreover, the on/off current ratio is over 103, and the retention time is up to 8 × 103 s, indicating the low misreading rate and high stability of data storage. So far, the value of power is about 10 times lower than those of the previous GO-based memories. The bilayer architecture provides a promising approach to construct intrinsic low-power resistive memory devices.

Ampholine immobilized polymer microspheres for increasing coverage of human urinary proteome.

Urinary proteome, as an important component of body fluid proteome, could reflect kidney, urogenital tract function and pathological changes of human organs. This study reports a convenient strategy for urine proteome analysis through ampholine immobilized polymer microsphere (ampholine@PM) fractionation strategy. After ampholine@PM treatment, 16,543 unique peptides corresponding to 2173 non-redundant urinary proteins were identified, while only 856 proteins, corresponding to 3524 peptides were identified in the crude urine sample. The number of proteins and peptides was increased by 1.54 and 3.69 times, respectively. 31 urinary candidate biomarkers have also been identified (17 candidate biomarkers of glomerular injury and 14 candidate biomarkers of tubular injury), showing the potential of our strategy in urinary biomarker discovery study. In additional to the urine proteome, N-glycoproteome analysis was also performed after ampholine@PM fractionation followed by the N-glycopeptides enrichment. The number was increased from 144 to 281 for N-glycoproteins, 261 to 709 for N-glycopeptides, and 226 to 493 for N-glycosylation sites, after ampholine@PM treatment. Based on the significant increase on the identified N-glycoprotein number, ampholine@PM fractionation strategy also offered a beneficial tool for the post translational modification analysis of urine proteome.

Hierarchical Hollow-Pore Nanostructure Bilayer Heterojunction Comprising Conjugated Polymers for High-Performance Flash Memory.

We report the design and preparation of hierarchical hollow-pore nanostructure bilayer conjugated polymer films for high-performance resistive memory devices. By taking the merits of chemical and structural stabilities of a two-dimensional conjugated microporous polymer (2D CMP), a poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) film with a hollow surface was spin-coated onto 2D CMP nanofilm directly, constructing a bilayer heterojunction. A two-terminal diode with a configuration of indium tin oxide/2D CMP/hollow MEH-PPV/Al was fabricated by employing the prepared bilayer heterojunction. The device poses flash feature with a high on/off ratio (>105) and a long retention time (>3.0 × 104 s), which is higher than that of most of the reported conjugated polymers memories. Our work offers a general guideline to construct high on/off ratio polymer memories via hierarchical nanostructure engineering in memristive layer.

Aptamer functionalized magnetic graphene oxide nanocomposites for highly selective capture of histones.

The binding coverage of aptamer was an important restricted factor for aptamer-based affinity enrichment strategy for capturing target molecules. Herein, we designed and prepared aptamer functionalized graphene oxide based nanocomposites (GO/NH2 -NTA/Fe3 O4 /PEI/Au), and the coverage density of aptamer was high to 33.1 nmol/mg. The high aptamer coverage density was contributed to the large surface area of graphene oxide. The successive modification of Nα,Nα-Bis(carboxymethyl)-L-lysine, magnetic nanoparticles, polyethylenimine, and Au nanoparticles ensured the histone purification with fast speed and high purity. Histones could be captured rapidly and specifically from nucleoproteins by our aptamer based purification strategy, while traditional acid-extraction could not specifically enrich histones. Compared with traditional acid-extraction method, rapid and efficient discovery of histones and their post-translational modifications, such as several kinds of methylation at H3.1K9 and H3.1K27, were achieved confidently. It demonstrated that our aptamer functionalized magnetic graphene oxide nanocomposites have a great potential for histone analysis.

Artificial Antibody with Site-Enhanced Multivalent Aptamers for Specific Capture of Circulating Tumor Cells.

Isolation of circulating tumor cells (CTCs) from blood holds great potential to diagnose cancers and discover therapeutic targets. Herein, we reported a novel kind of artificial antibody, the cell-imprinted hydrogel with site-directed modification of aptamers (APT-CIH) to achieve the specific capture of CTCs. Cell-imprinted sites not only could be used to recognize target cells but also could be used as efficient scaffolds for assembling aptamers to enhance the capture efficiency and selectivity. Due to the synergistic effect of conformation recognition and multivalent interaction between the aptamers and target cells, APT-CIH showed high capture efficiency and selectivity to SMMC-7721 cells. In the coexistence of the 1000 times leukemia Jurkat cells, the enrichment factor of APT-CIH could reach as high as 21.6 ± 3.1 toward target cells, while that relied only on cell imprinting or aptamer affinity was 8.1 ± 5.0 or 10.1 ± 1.3, respectively. Furthermore, the capture efficiency could reach 58.2% ± 10.9% with 1000 SMMC-7721 cells spiked in 1 mL of blood. Moreover, 92% of the captured cells could be released, beneficial to carry out further biological and clinical study of CTCs. These results demonstrated that APT-CIH might have great potential in CTCs analysis.

Hexagonal Ti2B2 monolayer: a promising anode material offering high rate capability for Li-ion and Na-ion batteries.

Combining the first-principles density functional method and crystal structure prediction techniques, we report a series of hexagonal two-dimensional transition metal borides including Sc2B2, Ti2B2, V2B2, Cr2B2, Y2B2, Zr2B2, and Mo2B2. Their dynamic and thermal stabilities are testified by phonon and molecular dynamics simulations. We investigate the potential of the two-dimensional Ti2B2 monolayer as an anode material for Li-ion and Na-ion batteries. The Ti2B2 monolayer possesses high theoretical specific capacities of 456 and 342 mA h g-1 for Li and Na, respectively. The very high Li/Na diffusivity with an ultralow energy barrier of 0.017/0.008 eV indicates an excellent charge-discharge capability. In addition, good electronic conductivity during the whole lithiation process is found by electronic structure calculations. The very small change in volume after the adsorption of one, two, and three layers of Li and Na ions indicates that the Ti2B2 monolayer is robust. These results highlight the suitability of Ti2B2 monolayer as well as the other two-dimensional transition metal borides as excellent anode materials for both Li-ion and Na-ion batteries.

Surface sieving coordinated IMAC material for purification of His-tagged proteins.

Tailor-made materials for the purification of proteins with His-tag was designed through synergizing the selectivity of surface sieving and metal ion affinity. By excluding impurity proteins out of the surface polymer network, such materials could purify His-tagged proteins from the crude cell lysis with purity up to 90%, improved by 14% compared to that obtained by the commercial metal chelating affinity materials. This study might promote the His-tagged protein purification to a new level.

A robust and effective intact protein fractionation strategy by GO/PEI/Au/PEG nanocomposites for human plasma proteome analysis.

Identification of human plasma proteins with deep coverage is considered as a great challenge due to its extreme complexity. In this work, an intact proteins fractionation strategy based on multi-interaction between proteins and GO/PEI/Au/PEG nanocomposites (GPAP strategy) was developed for human plasma proteome deep analysis. Compared with untreated method, the number of identified proteins was increased from 858 to 2023, among which the number of low-abundance proteins (< 100ng/mL) was increased from 2 to 11. The concentration range of the identified proteins was broaden to 9 orders of magnitude. Furthermore, the spectral count of the top three proteins in human plasma (Plasma Albumin, Human IgG, Serotransferrin) were decreased in the range of 37.4-82.6%. An excellent reproducibility of GPAP strategy was verified via stable isotope dimethyl label strategy. The functionalized material was demonstrated to be an efficient method to achieve deep coverage identification of human plasma proteome.

Aptamer-immobilized open tubular capillary column to capture circulating tumor cells for proteome analysis.

Circulating tumor cells hold the key to predicting the prognosis and discovering the therapeutic targets. Herein, we proposed a strategy to develop an aptamer-immobilized open tubular capillary column by which SMMC-7721 human hepatoma cells (SMMC-7721 cells) could be captured with an over 70% of capture efficiency and a 3.0 ± 0.2 of enrichment factor. Owing to the compatibility of the column, the captured cells by the column could be analyzed by LC-MS from protein level and 5 unique proteins of SMMC-7721 cells were identified which could be used as markers to identify SMMC-7721 cells when Jurkat T-leukemia cells (Jurkat cells) were employed as interfering cells. As the key component, the aptamer-immobilized column had the potential to be integrated into the platform for separating, enriching and characterizing rare cells simultaneously.

Gold-Coated Nanoelectrospray Emitters Fabricated by Gravity-Assisted Etching Self-Termination and Electroless Deposition.

To improve the stability and sensitivity of nanoelectrospray for liquid chromatography-mass spectroscopy (LC-MS) analysis, we present a new method to fabricate gold-coated emitters. Via gravity-assisted etching self-termination, the emitter with a tapered outer surface and a straight inner surface is prepared with good reproducibility, without the need of fluid introduced to protect internal surface during etching. Followed by electroless deposition, the emitter is further coated with gold film homogeneously, by which the relative standard deviation (RSD) value of total ion current in 160 h is <5%, showing good stability. Compared to that obtained by a commercial emitter, the identified protein number from 2 µg HeLa cell digests is increased over 10%, contributed by the stable electrospray and improved signal intensity of peptides. Furthermore, the integrated gold-coated emitter is prepared at the end of the ultranarrow-bore packed column (inner diameter of 25 µm), and 218 proteins are identified from 2 ng HeLa cell digests. All of these results demonstrate the great promise of such emitters for use in ultrasensitive proteome analysis.

Rhamnolipid-enhanced aerobic biodegradation of triclosan (TCS) by indigenous microorganisms in water-sediment systems.

Bioremediation of triclosan (TCS) is a challenge because of its low bioavailability, persistence in the environment and recalcitrance to remediation efforts. Rhamnolipid (RL) was used to enhance TCS biodegradation by indigenous microbes in an aerobic water-sediment system. However, knowledge of the effects of TCS on the bacterial community and environmental factors in an RL-enhanced, TCS-degrading system are lacking. Therefore, in this study, the influence of environmental factors on RL-enhanced biodegradation of TCS was investigated by single factor experiments, and shifts in aerobic TCS-degrading bacterial populations, with and without RL, were analyzed by high-throughput sequencing technology. The results showed that aerobic biodegradation of TCS was significantly promoted by the addition of RL. Environmental conditions, which included RL addition (0.125-0.5g/L), medium concentrations of TCS (<90µg/g), water disturbance, elevated temperature, ionic strength (0.001-0.1mol/L NaCl) and weak alkaline environments (pH8-9), were monitored. High concentrations of TCS had a remarkable influence on the bacterial community structure, and this influence on the distribution proportion of the main microorganisms was strengthened by RL addition. Alpha-proteobacteria (e.g., Sphingomonadaceae and Caulobacteraceae) might be resistant to TCS or even capable of TCS biodegradation, while Sphingobacteria, Beta- and Delta-proteobacteria were sensitive to TCS toxicity. This research provides ecological information on the degradation efficiency and bacterial community stability in RL-enhanced bioremediation of TCS-polluted aquatic environments.