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Background & Aims: We aimed to determine the trends in risk factor control and treatment among patients with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D) in 2000-2020. Methods: We conducted a territory-wide cohort study of adult patients with NAFLD and T2D diagnosed between 1 January 2000 and 31 July 2021 in Hong Kong. T2D was defined by use of any anti-diabetic agents, laboratory tests and/or diagnosis codes. Results: This study included 16,084 patients with NAFLD and T2D (mean age, 54.8 ± 12.0 years; 7124 male [44.3%]). The percentage of patients achieving individualised haemoglobin A1c (HbA1c) targets increased from 44.5% (95% confidence interval [CI], 42.9-46.1) to 64.8% (95% CI, 64.1-65.5), and percentage of patients achieving individualised low-density lipoprotein-cholesterol (LDL-C) targets increased from 23.3% (95% CI, 21.9-24.7) to 54.3% (95% CI, 53.5-55.1) from 2000-2005 to 2016-2020, whereas percentage of patients achieving blood pressure control (<140/90 mm Hg) remained static at 53.1-57.2%. Combination therapy for diabetes increased, especially among those with poor glycaemic control, but there was no increase in combination therapy for hypertension. Fewer cirrhotic patients achieved blood pressure control and individualised LDL-C targets, but they were more likely to achieve individualised HbA1c targets than non-cirrhotics. Metformin and statins were underused in cirrhotic patients. Younger patients (18-44 years) were less likely to achieve individualised HbA1c targets than middle-aged (45-64 years) and older ones (=65 years). Conclusions: From 2000 to 2020, glycaemic and lipid control improved significantly, whereas blood pressure control remained static among patients with NAFLD and T2D. [ABSTRACT FROM AUTHOR]

This paper puts forward the robust control problem of rail vehicle virtual coupling platoon that is subject to nonlinear and time-varying uncertainties. The uncertainties are caused by external disturbances and parameter variations. To this end, this paper designs a robust controller based on the Udwadia-Kalaba (UK) equation. First, we introduce the concept of virtual coupling and establish the longitudinal dynamics model of the rail vehicle. In order to ensure the control objective of the virtual coupling process, the spatial constraint on position and bidirectional inequality constraints for the spacing error between the marshalling trains are established. After changing the bounded state into the unbounded state through the state transformation, the UK approach can be used. Then, the constraint-following robust controller design is based on the UK approach and Lyapunov stability theory. The controller can render the unbounded state eventual uniform boundedness and uniformultimate boundedness, which also satisfies the spatial constraint and the bidirectional restriction for the spacing error. Moreover, an optimized design scheme for the tunable parameter of this controller is proposed, which minimizes the control cost and comprehensive index of system performance. Finally, numerical simulations are given to illustrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

A novel robust approach for the obedience control of Furuta pendulum with uncertainty is proposed. The uncertainty considered in this paper is (possibly fast) time-varying and bounded, which may exist in any stage of the pendulum subsystem. By the Lagrangian formulation of the nonlinear pendulum system, a robust control, based on a general Lyapunov function, is designed to render the Furuta pendulum a position obedience. As a consequence of the Lyapunov approach, the control design is not restricted to linearize the pendulum system. The system performance under the proposed control is guaranteed as uniform boundedness and uniform ultimate boundedness. The salient features of this new control are demonstrated both analytically and numerically. The experiment is conducted in the Furuta pendulum system to prove the validity and effectiveness of the control design. [ABSTRACT FROM AUTHOR]

ZrO2−carbon nanotube (CNT) composites have been successfully synthesized via decompositoin of Zr(NO3)4·5H2O in supercritical carbon dioxide−ethanol solution with dispersed CNTs at relatively low temperatures. The samples were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) analyses. It was demonstrated that CNTs were fully coated with an amorphous ZrO2layer, and the coating layer was nominally complete and uniform. In addition, the thickness of the coating sheath could be readily controlled by tuning the Zr(NO3)4·5H2O/CNTs ratio used. Furthermore, the chemiluminescent sensor prepared from ZrO2−carbon nanotube composites exhibited dramatic sensitivity as well as high stability and selectivity to ethanol. [ABSTRACT FROM AUTHOR]

The problem of laminar natural convection on a vertical baffled plate subjected to a periodic oscillation is investigated numerically. Of particular interest of this paper is the heat transfer characteristic with the oscillatory velocity being close to the flow velocity in the velocity boundary layer under nonoscillation condition. The results show that a sevenfold increase in space-time averaged Nusselt number is achieved. Three mechanisms that are responsible for the heat transfer enhancement are identified. In addition, the effects of the governing parameters on the heat transfer are studied over a wide range. The heat transfer enhancement is found to be increased with dimensionless oscillation frequency and amplitude, but decreased with the Grashof number. Another interest of this paper is to optimize the geometry of baffle plates and an optimal baffle height-spacing ratio 0.25-0.50 is found for higher heat transfer rate. [ABSTRACT FROM AUTHOR]

Fast screening for anabolic steroids in whole urine is achieved by combining reactive desorption electrospray ionization (reactive DESI) and tandem mass spectrometry. Spray solutions containing hydroxylamine allow heterogeneous reactions of hydroxylamine with the carbonyl group of the steroids during the ionization process. Seven steroids, including a glycosteroid, were examined. The ion/molecule reaction adduct and the oxime formed via its dehydration were observed using reactive DESI; the protonated and sodiated forms of the ionized steroid were also observed both in reactive DESI and in DESI performed without the added hydroxylamine reagent. Paper, glass, and polytetrafluoroethylene were tested as sample substrates, but the glycosteroid was ionized intact without hydrolysis only from polytetrafluoroethylene. Limits of detection for the pure compounds were less than 1 ng, dynamic ranges were typically 2 orders of magnitude, and analysis times were just a few seconds. Concentration levels of ketosteroids in raw urine relevant to screening for sports doping (approximately 20 ng/mL) can be reached using a simple solid-phase microextraction (SPME) preconcentration step. Reactive DESI provided significant improvements in ionization efficiency of these steroids in raw undiluted urine as compared to conventional DESI; suppression effects due to the sample matrix were minimal and the urine matrix had no deleterious effect on steroid detection limits. Tandem mass spectrometry provided confirmation of analyte identification in this rapid screening process. [ABSTRACT FROM AUTHOR]

Mass spectrometry imaging (MSI) has important applications in material research, biology, and medicine. The MSI method based on UV laser desorption/ionization (UVLDI) can obtain images of intact samples, but has a high level of molecular fragmentation. In this work, we report a new MSI instrument that uses a VUV laser (125.3 nm) as a desorption/ionization source to exploit its advantages of high single photon energy and small focus size. The new instrument was tested by the mass spectra of Nile red and FGB (Fibrinogen beta chain) samples and mass spectrometric images of a fly brain section. For the tested samples, the VUVDI method offers lower levels of molecular fragmentations and higher sensitivities than those of the UVLDI method and second ion mass spectrometry imaging method using a Bi3+ beam. The ablation crater produced by the focused VUV laser on a quartz plate has an area of 10 μm2. The VUV laser is prepared based on the four-wave mixing method using three collimated laser beams and a heated Hg cell. [ABSTRACT FROM AUTHOR]

Long non-coding RNAs (lncRNAs) have emerged recently as important factors in regulating fundamental biological processes. Alterations in the expression and function of lncRNAs have been observed to promote tumor formation, progression and metastasis. Although downregulation of the expression levels of LET lncRNA in several tumors has been reported, its role in gastric cancer remains unknown. The aim of the present study was to investigate the expression and function of LET in gastric cancer development. The expression levels of LET in 37 pairs of gastric cancer and adjacent non-tumor tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, LET expression in gastric cancer cell lines was analyzed by RT-qPCR assay analysis. Furthermore, the impact of LET on cell proliferation, migration and apoptosis were detected using the cell counting kit-8, wound scratch and ELISA assays, respectively. The results demonstrated that the expression level of LET was downregulated in gastric cancer tissues and cell lines (SGC-7901 and MGC-803) compared with normal tissues and a normal human gastric epithelial cell line (GES-1). Restoration of LET expression using a synthesized recombinant overexpression vector transfected into SGC-7901 and MGC-803 cells, significantly inhibited cell proliferation and migration, and promoted cell apoptosis in vitro. The present study is the first to demonstrate that LET may function as a tumor suppressor in gastric cancer. The results indicate that LET may be a promising biomarker and/or a therapeutic target for gastric cancer. [ABSTRACT FROM AUTHOR]

Current detection methods for paper-based analytical devices (PADs) rely on spectroscopic and electrochemical properties, which place special requirements on the analyte or need analyte labeling. Here, ion-transmission mass spectrometry (MS) was proposed for coupling with PADs to enable rapid in situ MS analysis of the sample on paper. The sample was analyzed directly on paper via analyte ionization by ions transmitted through the paper, generated by a low-temperature plasma probe. Prior to MS analysis, the sample can be separated by paper electrophoresis or by paper chromatography, among a variety of other features offered by PADs. The versatility of this technique was demonstrated by MS analysis of a paper microarray, a nurture of amino acids, and whole blood doped with drugs on PADs. [ABSTRACT FROM AUTHOR]

Conspectus: The unambiguous quantification of biomolecules is of great significance in fundamental biological research as well as practical clinical diagnosis. Due to the lack of a detectable moiety, the direct and highly sensitive quantification of biomolecules is often a "mission impossible". Consequently, tagging strategies to introduce detectable moieties for labeling target biomolecules were invented, which had a long and significant impact on studies of biomolecules in the past decades. For instance, immunoassays have been developed with radioisotope tagging by Yalow and Berson in the late 1950s. The later languishment of this technology can be almost exclusively ascribed to the use of radioactive isotopes, which led to the development of nonradioactive tagging strategy-based assays such as enzyme-linked immunosorbent assay, fluorescent immunoassay, and chemiluminescent and electrochemiluminescent immunoassay. Despite great success, these strategies suffered from drawbacks such as limited spectral window capacity for multiplex detection and inability to provide absolute quantification of biomolecules. After recalling the sequences of tagging strategies, an apparent question is why not use stable isotopes from the start? [ABSTRACT FROM AUTHOR]

We had developed pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS) for systematically profiling and determining components in small volume sample. Pulsed-dc-ESI utilized constant high voltage to induce the generation of single polarity pulsed electrospray remotely. This method had significantly boosted the sample economy, so as to obtain several minutes MS signal duration from merely picoliter volume sample. The elongated MS signal duration enable us to collect abundant MS2 information on interested components in a small volume sample for systematical analysis. This method had been successfully applied for single cell metabolomics analysis. We had obtained 2-D profile of metabolites (including exact mass and MS2 data) from single plant and mammalian cell, concerning 1034 components and 656 components for Allium cepa and HeLa cells, respectively. Further identification had found 162 compounds and 28 different modification groups of 141 saccharides in a single Allium cepa cell, indicating pulsed-dc-ESI a powerful tool for small volume sample systematical analysis. [ABSTRACT FROM AUTHOR]

Sensitive detection of biomolecules in small-volume samples by mass spectrometry is, in many cases, challenging because of the use of buffers to maintain the biological activities of proteins and cells. Here, we report a highly effective desalting method for picoliter samples. It was based on the spontaneous separation of biomolecules from salts during crystallization of the salts. After desalting, the biomolecules were deposited in the tip of the quartz pipet because of the evaporation of the solvent. Subsequent detection of the separated biomolecules was achieved using solvent assisted electric field induced desorption/ionization (SAEFIDI) coupled with mass spectrometry. It allowed for direct desorption/ionization of the biomolecules in situ from the tip of the pipet. The organic component in the assistant solvent inhibited the desorption/ionization of salts, thus assured successful detection of biomolecules. Proteins and peptides down to 50 amol were successfully detected using our method even if there were 3 x 105 folds more amount of salts in the sample. The concentration and ion species of the salts had little influence on the detection results. [ABSTRACT FROM AUTHOR]

Complex biologicalmatrices can be effectively removed in the analyte migration process because of their weak solubility in organic solvents. This technique offers other potential advantages, including high-sensitivity and the capability of performing a direct analysis of the components and their metabolites in small-volume raw samples without any pretreatment. [ABSTRACT FROM AUTHOR]

The discrimination of the type of cancer cells remains challenging due to the subtle differences in their expression of membrane receptors. In this work, we developed a multicolor cell imaging method for distinguishing the type of cancer cells with fluorophore-tagged aptamers. We found that the interaction between aptamers and cancer cells was affected by both of the sequence of aptamers and the labeled dyes. As the co-ownership of biomarkers for different cancer cell lines, the fluorophore-tagged aptamers interacted with different cancer cell lines in different degree, resulting in a distinct color to discriminate the type of cancer cells at single cell level. Taking advantage of the cross-reactive ability of the fluorophore-tagged aptamers, we could not only distinguish the cancerous cells quickly from large quantities of noncancerous cells, but also identify the type of the cancerous cells. This work has potential application for cancer diagnostic and therapy in the future. [ABSTRACT FROM AUTHOR]

With the inspiration of an ancient Chinese poison test approach, we report a rapid hydrogen sulfide detection strategy in specific areas of live cells using silver needles with good spatial resolution of 2 × 2 μm². Besides the accurate-localization ability, this reflection-based strategy also has attractive merits of convenience and robust response when free pretreatment and short detection time are concerned. The success of endogenous H2S level evaluation in cellular cytoplasm and nuclear of human A549 cells promises the application potential of our strategy in scientific research and medical diagnosis. [ABSTRACT FROM AUTHOR]

Molecular analysis at cellular and subcellular levels, whether on selected molecules or at the metabolomics scale, is still a challenge now. Here we propose a method based on probe ESI mass spectrometry (PESI-MS) for single cell analysis. Detection of metabolites at cellular and subcellular levels was successfully achieved. In our work, tungsten probes with a tip diameter of about 1 μm were directly inserted into live cells to enrich metabolites. Then the enriched metabolites were directly desorbed/ionized from the tip of the probe for mass spectrometry (MS) detection. The direct desorption/ionization of the enriched metabolites from the tip of the probe greatly improved the sensitivity by a factor of about 30 fold compared to those methods that eluted the enriched analytes into a liquid phase for subsequent MS detection. We applied the PESI-MS to the detection of metabolites in single Allium cepa cells. Different kinds of metabolites, including 6 fructans, 4 lipids, and 8 flavone derivatives in single cells, have been successfully detected. Significant metabolite diversity was observed among different cells types of A. cepa bulb and different subcellular compartments of the same cell. We found that the inner epidermal cells had about 20 fold more fructans than the outer epidermal cells, while the outer epidermal cells had more lipids. We expected that PESI-MS might be a candidate in the future studies of single cell "omics". [ABSTRACT FROM AUTHOR]

A multiplex DNA assay based on nanoparticle (NP) tags detection utilizing single particle mode inductively coupled plasma mass spectrometry (SP-ICP-MS) as ultrasensitive readout has been demonstrated in the article. Three DNA targets associated with clinical diseases (HIV, HAV, and HBV) down to 1 pM were detected by DNA probes labeled with AuNPs, AgNPs, and PtNPs via DNA sandwich assay. Single nucleotide polymorphisms in genes can also be effectively discriminated. Since our method is unaffected by the sample matrix, it is well-suited for diagnostic applications. Moreover, with the high sensitivity of SP-ICP-MS and the variety of NPs detectable by SP-ICP-MS, high-throughput DNA assay could be achieved without signal amplification or chain reaction amplification. [ABSTRACT FROM AUTHOR]

Selective activation of benzene has been mainly limited to the C-H activation. Simple replacement of one carbon in benzene with another atom remains unresolved due to the high dissociation energy. Herein, we demonstrate a direct breakage of the particularly strong C=C bond in benzene through ion-molecule reaction in a low-temperature plasma, in which one carbon atom was replaced by one atomic nitrogen with the formation of pyridine. The mechanism for the formation of pyridine from benzene has been proposed based on the extensive investigation with tandem mass spectrometry. The reaction pathway also works to other aromatics such as toluene and o-xylene. This finding provides a new avenue for selective conversion of aromatics into nitrogen-containing compounds. [ABSTRACT FROM AUTHOR]

We developed a colorimetric sensor array with reported protein aptamers as nonspecific receptors. We found that different target proteins could make the aptamer-protected gold nanoparticles (AuNPs) exhibit different aggregation behaviors in the presence of a high concentration salt and cause various color change. On the basis of this phenomenon, we applied a series of reported protein aptamers as a receptor array obtaining a distinct response pattern to each target protein. Seven proteins have been well distinguished with the naked eye at the 50 nM level. Cancerous human cells have also been discriminated from noncancerous cells. This method is simple, label-free, and sensitive. It will broaden the application filed of plasmonic nanoparticle-based sensors and give a new direction of developing sensitive array sensing systems. [ABSTRACT FROM AUTHOR]

Fluorescent gold nanoparticle (GNP) is an easily synthesized and biocompatible optical platform for sensing and imaging with tunable near-infrared (NTR) emission. However, the relatively low fluorescence (FL) quantum yield limits the further improvement of sensitivity and application. Here, we find that, on plasmonic substrates, the FL intensity of protein-directed synthesized GNPs can be enhanced significantly (~20-fold). Moreover, protein analytes can interact with GNPs and influence the enhanced fluorescence process so that we can obtain distinct FL image patterns. Then, using the array-based sensing strategy, protein discrimination can be achieved. In our present experiment, five GNPs were used as sensing elements and 10 kinds of proteins at three concentrations (0.2, 03, and 1 μM) were successfully identified. This array-based sensing strategy using enhanced-fluorescence from GNPs is highly sensitive and differentiable, expanding the application field of GNPs. [ABSTRACT FROM AUTHOR]

The method for the localization of bioactive molecules in plants is highly needed since it provides a fundamental prerequisite for understanding their physiological and ecological functions. Here, we propose a simple method termed in vivo nanoelectrospray for the localization of bioactive molecules in plants without sample preparation. A capillary is partly inserted into the plant to sample liquid from a highly located region, and then, a high voltage is applied to the plant to generate an electrospray from the capillary tip for mass spectrometry analysis. Using this method, bioactive molecules such as saccharides, glycoalkaloids, flavonoids, organic acids, and glucosinolates (GLs) are detected in the target regions of living plants or fresh fruits. Original information for endogenous chemicals including liable molecules in plant can be obtained. A sketchy three-dimensional distribution of glycoalkaloids in a cherry tomato has been obtained. The present work provides a powerful tool for the study of bioactive molecules in a living plant by mass spectrometry. [ABSTRACT FROM AUTHOR]

Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the -OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy. [ABSTRACT FROM AUTHOR]

A novel ionization device for controlling the charge states of peptides based on an inductive elecrospray ionization technique was developed. This ion source keeps the major capabilities of electrospray ionization (ESI) which is compatible with liquid separation techniques (such as liquid chromatography (LC) and capillary electrophoresis (CE)) and can be potentially used to control the charge states of peptides accurately by simply varying the AC voltage applied. In comparison with conventional ESI, inductive ESI successfully simplifies the mass spectrum by reducing the charge states of peptide to a singly charged one, as well as eliminating the adductions. [ABSTRACT FROM AUTHOR]

The fluorescence of metal nanoclusters provides an amusing optic feature to be applied in various fields. However, rational design of dual functional fluorescent metal nanoclusters directed by active enzyme with targeted application remains little explored. In this work, we report a new strategy to construct enzyme functionalized fluorescent gold nanoclusters via a biomineralization process for the detection of hydrogen peroxide. Horseradish peroxidase (HRP) was used as a model functional template to direct the synthesis of fluorescent gold nanoclusters (Au NCs) at physiological conditions to form HRP—Au NCs bioconjugates. We found that the fluorescence of HRP-Au NCs can be quenched quantitatively by adding H2O2 indicating that HRP enzyme remains active and enables catalytic reaction of HRP-Au NCs and H2O2. Upon the addition of H2O2 under optimal conditions, the fluorescence intensity quenched linearly over the range of 100 nM to 100 μM with high sensitivity (LOD = 30 nM, S/N = 3). This study would be potentially extended to other functional proteins to generate dual functional nanoclusters and applied to real time monitoring of biologically important targets in living cells. [ABSTRACT FROM AUTHOR]

The development of material science increasingly calls for rapid characterization methods with low limits of detection and high spatial resolution. Here we report a depth profile analysis method for thin layer coatings by combining low temperature plasma (LTP) probe with inductively coupled plasma mass speclrometiy (ICP-MS). The LTP probe with diameter of several tens of micrometers served as a tool for mass removal, which is generated by the discharge in a quartz capillaiy at ambient condition. The sample material is ablated by the LTP probe and converted into an aerosol, and transported by a carrier gas flow to the ICP-MS, where the decomposed and ionized aerosol particles are analyzed with high sensitivity. Scanning electron microscope (SEM) micrographs reveal that the trace after ablation by the LTP probe is a hole with a diameter less than 10 pm. A lateral resolution of approximately 200 pm has been achieved by analyzing an electron component with interval metal stripes. Depth profiling of a 100 nm single layer sample and a multiple layer sample (100 nm Al/250 nm SiOillOO nm Au150 nm Cr) on a silicon substrate have been successfully performed at ambient condition. The present method offers unique advantages in terms of high spatial resolution, fast analysis speed and ease of implementation. It might be considered a complementary technique to existing depth profiling methods such as GDMS/OES, AES, and SIMS. In addition, the simple-to fabricate LTP probe is easily coupled to various other elemental analysis tools for thin layer or direct solid sample analysis in micro area. [ABSTRACT FROM AUTHOR]

A simple and fast (<5 s) method for in situarsenic speciation on solid surfaces has been developed based on desorption electrospray ionization-tandem mass spectrometry (DESI-MS). Arsenic-polluted environmental samples such as animal feed and plant tissues could be directly monitored by DESI-MS. Each arsenic species in this study, including monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), arsenocholine (AsC), 4-arsanilic acid (p-ASA), 4-hydroxyphenylarsonic acid (4-OH), Nitarsone, Roxarsone and two inorganic arsenic species, arsenate As(v) and arsenite As(iii), could be detected by their typical m/zand collision induced dissociation (CID) behavior respectively. By the characteristic information, mixtures of different arsenic species could be detected without any sample preparation and separation process. This method could give absolute detection limits of the arsenic species at ng/mm2to pg/mm2level with a best RSD of 5.3% (n= 5). The method could be potentially applied to in situenvironmental monitoring of arsenic pollution, especially that caused by arsenic pesticides, animal feed additives, herbicides and wood treatment. [ABSTRACT FROM AUTHOR]

In this paper, we report on biomineralization of BaCO3 hierarchical architectures with self-cleaning ability. The phase structures of the obtained samples were charactenzed by X-ray diffraction (XRD). Allot these complex nanostructures, including dendrite-like nanostnictures, dumbbell-like nanostructures, and spherical nanostructures of BaCO3, were obtained by tuning the experimental parameters, such as the concentration of glucosan and Ba2+ cations. The morphology and structures were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), and Fourier transform infrared (FT-lR) spectrum. The formation of dendrite-like, dumbbell-like, and spherical complex nanostructures can be explained by a rod-dumbbell-sphere (ADS) self-assembly growth mechanism. To our knowledge, this is the first demonstration of the biomimetic synlhesis of BaCO3 hierarchical architectures which uniquely display the characteristic of superhydrophobicity. A water contact angle of >1500 and sliding angle of 10 of the BaCO3 hierarchical archdeclures can be adjusted, which opens up a wide range of new potential applications of bioinspired complex nanostructures in environmental chemistry. [ABSTRACT FROM AUTHOR]

A high-throughput method for rapid screening of active ingredients in drugs has been developed with mass spectrometry coupled to a low-temperature plasma (LTP) probe ion source. Without sample preparation or pretreatment, the active ingredients of 11 types of commercial pharmaceuticals, including hormones, antipyretic analgesics, cardiovascular, digestant, neuro-psychotherapeutic, diuretic, antithyroid, sulfa anti-inflammatory, antiparastic, sedative-hypnotics, and antibacterial, were directly desorbed/ionized and detected by a linear ion trap mass spectrometry (MS). The structures of these ingredients were elucidated by tandem MS. The analysis of 18 methyltestosterone tablets could be accomplished within 1.9 min, which allows fast detection with a speed of approximate 600 samples within 1 h. This work demonstrated that LTP probe ion source combined with MS is a high-throughput method for screening of pharmaceuticals and potentially applied to on-line quality control in pharmaceutical industry. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Real-time and in-situmonitoring of ongoing chemical reactions by mass spectrometry was achieved by simply directing the low-temperature plasma (LTP) to the surface of the reaction system for analyte desorption and ionization without any sample pretreatment. [ABSTRACT FROM AUTHOR]

The effects of SeIV on the structure and function of recombinant human arsenic (+3 oxidation state) methyltransferase (AS3MT) purified from the cytoplasm of Escherichia coli were studied. The coding region of human AS3MT complementary DNA was amplified from total RNA extracted from HepG2 cell by reverse transcription PCR. Soluble and active human AS3MT was expressed in the E. coli with a Trx fusion tag under a lower induction temperature of 25 °C. Spectra (UV–vis, circular dichroism, and fluorescence) were first used to probe the interaction of SeIV and recombinant human AS3MT and the structure–function relationship of the enzyme. The recombinant human AS3MT had a secondary structure of 29.0% α-helix, 23.9% β-pleated sheet, 17.9% β-turn, and 29.2% random coil. When SeIV was added, the content of the α-helix did not change, but that of the β-pleated sheet increased remarkably in the conformation of recombinant human AS3MT. SeIV inhibited the enzymatic methylation of inorganic AsIII in a concentration-dependent manner. The IC50 value for SeIV was 2.38 μM. Double-reciprocal (1/ V vs. 1/[inorganic AsIII]) plots showed SeIV to be a noncompetitive inhibitor of the methylation of inorganic AsIII by recombinant human AS3MT with a Ki value of 2.61 μM. We hypothesized that SeIV interacts with the sulfhydryl group of cysteine(s) in the structural residues rather than the cysteines of the active site (Cys156 and Cys206). When SeIV was combined with cysteine(s) in the structural residues, the conformation of recombinant human AS3MT changed and the enzymatic activity decreased. Considering the quenching of tryptophan fluorescence, Cys72 and/or Cys226 are deduced to be primary targets for SeIV. [ABSTRACT FROM AUTHOR]

High-throughput screening of catalysts could dramatically improve performance and reduce costs in the discovery and study of various catalysts. Here we report a cataluminescence-based array imaging as a high-throughput screening technique in the combinatorial discovery of active catalysts for CO oxidation. This strategy is based on the fact that the CO oxidation generates cataluminescence emission on the surface of nanomaterials, whose intensity is correlated to the activity of the catalyst. To demonstrate the feasibility of the cataluminescence-based array imaging for high-throughput screening of catalysts, different nanosized metal catalysts supported on TiO2 nanoparticles were prepared. These catalysts include monometallic Au, Pt, and the bimetallic Au-Pt heteroaggregate catalysts, at total metal loadings of 0.5%, 1.0%, and 2.5%, and with atomic ratios of 1:1, 1:2, and 2:1 (Au/Pt). A 4 × 4 array was integrated by depositing these nanosized catalysts onto the ceramic chip, and the brightness of each spot in the image was recorded. The catalytic activities of those catalysts for the CO oxidation were evaluated parallelly by both the cataluininescence imaging and the gas chromatography method. The correlation coefficient is 0.9 14 for the two techniques, indicating that the cataluminescence imaging technique can be applied for the evaluation of the catalytic activities. Moreover, fast evaluation of multiple catalysts at a series of working temperature can be achieved by this cataluininescene-based array imaging. With the development of nanotechnology as well as the catalyst industry, the cataluminescence-based array imaging will address its importance in the high-throughput screening of catalysts. [ABSTRACT FROM AUTHOR]

A cross-reactive chemiluminescence (CL) sensor array based on catalytic nanomaterials was constructed for the discrimination and identification of flavors in cigarettes. A total of 21 nanomaterials, including metal oxides, metal oxides deposited on carbon nanotubes (CNTs), gold nanoparticles deposited on metal oxides, and carbonate, have been carefully selected as sensing elements of the array. Each flavor gives its unique CL pattern from the array, which is able to be employed for the discrimination and identification of flavors. Hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) were used to analyze the patterns. The obtained CL patterns are temperature dependent, thus additional discrimination power could be provided by changing the working temperature of the array. Quantification of the flavors has been performed according to the emission intensity on the specific sensing element. The linear ranges of the sensor array for the flavors are in the range of 20-2000 ppmv with the limits of detection below 10 ppmv, which vary with the kinds of flavors. Six brands of cigarettes have been discriminated by their CL patterns obtained with the present sensor array. The robust and reversible response of this array, combined with its simple instrumentation, indicates the promise of this array for real world application. [ABSTRACT FROM AUTHOR]

In this paper, we have constructed a low temperature plasma (LTP) probe using dielectric barrier discharge (DBD) and employed it for the detection of explosives on a variety of substrates under ambient conditions. Upon discharge, a transient, low-temperature non-equilibrium plasma comprising ions, electrons and metastable atoms are generated between the electrodes. Three common explosives, 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-trinitro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN), were directly desorbed and ionized from solid surfaces, followed by subsequent analysis using the mass spectrometer in the negative ion mode. Limits of detection (LODs) were 500 fg for TNT, 1 pg for RDX, and 500 fg for PETN. The reliability of the method was characterized by a successful analysis of a mixture of the three explosives. The ion source also allowed direct detection of trace explosives on both conductive and non-conductive substrates, thus expanding the applicability of low temperature plasma desorption mass spectrometry. [ABSTRACT FROM AUTHOR]

A low-temperature plasma (LTP) probe has been developed for ambient desorption ionization. An ac electric field is used to induce a dielectric barrier discharge through use of a specially designed electrode configuration. The low-temperature plasma is extracted from the probe where it interacts directly with the sample being analyzed, desorbing and ionizing surface molecules in the ambient environment This allows experiments to be performed without damage to the sample or underlying substrate and, in the case of biological analysis on skin surfaces, without electrical shock or perceptible healing. Positive or negative ions are produced from a wide range of chemical compounds in the pure state and as mixtures in the gaseous, solution, or condensed phases, using He, Ar, N2, or ambient air as the discharge gas. Limited fragmentation occurs, although it is greater in the cases of the molecular than the atomic discharge gases. The effectiveness of the LTP probe has been demonstrated by recording characteristic mass spectra and tandem mass spectra of samples containing hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) from poly(tetrafluoroethylene) (PTFE) surfaces where limits of detection are as low as 5 pg. Other performance characteristics, when using a commercial ion trap mass spectrometer, include 3-4 orders of magnitude linear dynamic range in favorable cases. Demonstration applications include direct analysis of cocaine from human skin, determination of active ingredients directly in drug tablets, and analysis of toxic and therapeutic compounds in complex biological samples. Ionization of chemicals directly from bulk aqueous solution has been demonstrated, where limits of detection are as low as 1 ppb. Large surface area sampling and control of fragmentation by a simple adjustment of the electrode configuration during operation are other demonstrated characteristics of the method. [ABSTRACT FROM AUTHOR]

A low-power, atmospheric-pressure microplasma source based on a dielectric barrier discharge (DBD) has been developed for use in atomic emission spectrometry. The small plasma (0.6 mm × 1 mm × 10 mm) is generated within a glass cell by using electrodes that do not contact the plasma. Powered by an inexpensive ozone generator, the discharge ignites spontaneously, can be easily sustained in Ar or He at gas flow rates ranging from 5 to 200 mL min-1, and requires less than 1 W of power. The effect of operating parameters such as plasma gas identity, plasma gas flow rate, and residual water vapor on the DBD source performance has been investigated. The plasma can be operated without removal of residual water vapor, permitting it to be directly coupled with cold vapor generation sample introduction. The spectral background of the source is quite clean in the range from 200 to 260 nm with low continuum and structured components. The DBD source has been applied to the determination of Hg by continuous-flow, cold vapor generation and offers detection limits from 14 (He-DBD) to 43 pg mL-1 (Ar-DBD) without removal of the residual moisture. The use of flow injection with the He-DBD permits measurement of Hg with a 7.2 pg limit of detection, and with repetitive injections having an RSD of <2% for a 10 ng mL-1 standard. [ABSTRACT FROM AUTHOR]

An l-cysteine-assisted self-assembly process for constructing complex PbS from cubes to star and dendritic structures via hydrothermal routes is reported. In this process, l-cysteine (Cys) was used as both a sulfur source and a chelating reagent. The effects of the molar ratios of Cys/Pb 2+, the concentrations, reaction time and temperature on the self-assembly of PbS microcrystals were investigated. The X-ray diffraction (XRD) patterns confirmed the crystalline structure of PbS crystals. Raman spectroscopy helped to further demonstrate the purity of the products. Transmission electron microscopy (TEM) helped to determine the size and shape of the products. On the basis of systemic studies about the influence of experimental parameters on the products, possible evolution processes were proposed. The shape of PbS crystals was closely related to the relative growth rate of the {100} and {111} faces. The Cys/Pb 2+molar ratios, the concentrations, and the reaction temperatures influenced the growth rate of the {100} and {111} faces, which determined the final morphology of PbS microcrystals. [ABSTRACT FROM AUTHOR]

A novel vapor-generation technique is described for mercury determination in aqueous solutions. Without need for a chemical reducing agent, dissolved mercury species are converted to volatile Hg vapor in a solution cathode glow discharge. The generated Hg vapor is then transported to an inductively coupled plasma for determination by atomic emission spectrometry. Mercury vapor is readily generated from a background electrolyte containing 0.1 M HNO3. Vapor generation efficiency was found to be higher by a factor of 2-3 in the presence of low molecular weight organic acids (formic or acetic acids) or alcohols (ethanol). Optimal conditions for discharge-induced vapor generation and reduced interference from concomitant inorganic ions were also identified. However, the presence of chloride ion reduces the efficiency of Hg-vapor generation. In the continuous sample introduction mode, the detection limit was found to be 0.7 μg L-1, and repeatability was 1.2% RSD (n = 11) for a 20 μg L-1 standard. In comparison with other vapor generation methods, it offers several advantages: First, it is applicable to both inorganic and organic Hg determination; organic mercury (thiomersal) can be directly transformed into volatile Hg species without the need for prior oxidation. Second, the vapor-generation efficiency is high; the efficiency (with formic acid as a promoter) is superior to that of conventional SnCl2-HCl reduction. Third, the vapor generation is extremely rapid and therefore is easy to couple with flow injection. The method is sensitive and simple in operation, requires no auxiliary reagents, and serves as a useful alternative to conventional vapor generation for ultratrace Hg determination. [ABSTRACT FROM AUTHOR]

A simple and easy-to-build high-throughput analysis system was constructed. The system consisted of three major components: (1) a multichannel device with 16 parallel capillaries, (2) a desorption electrospray ionization (DESI) source, and (3) a linear ion trap mass spectrometer. When analyses were performed, the multichannel device was moved horizontally on a translation stage controlled by a step motor. Our design expands the functions of DESI, in which the liquid sample in capillary was driven out by the nebulizing gas, ionized, and then transferred to a mass spectrometer. To assess the high-throughput performance of the system, 5 mg/L 1,3-diethyl-1,3-diphenylurea (DDU) solution and 10 mg/L angiotensin 1 solution were alternatively loaded into the reservoirs and capillaries in the multichannel device. Results indicated that analyses of the all the samples in 16 capillaries were completed within 1.6 mm, which means a throughput of 600 samples/h. Reactive DESI experiment was also successfully performed with this system to show the feasibility of online derivatization. The relative standard deviations for a single capillary and five identical capillaries were 7.6 (n = 16) and 12.3%, respectively. Linear relative abundance response was achieved for DDU (r=0.9971). [ABSTRACT FROM AUTHOR]

Inductively coupled plasma mass spectrometry (ICPMS) has been successfully used for the detection of element-tagged biomolecules with the advantage of multielement capability. However, this technique cannot be used for microarray detection due to the necessity to dissolve the elemental tags before introducing them to the plasma source. Here, we report the detection of multiple proteins on each spot of the immuno-microarray by laser ablation ICPMS. α-Fetoprotein IgG (AFP), carcinoembryonic antigen (CEA), and human IgG, as model proteins, have been detected on the basis of sandwich-type immunoreactions on a microarray with Sm3+-labeled AFP antibody, Eu3+-labeled CEA antibody, and Au-labeled goat-anti-human IgG (GAB) as labeled antibodies. The detection limits were 0.20, 0.14, and 0.0 12 ng mL-1 (3σ) with the RSD of 5.7%, 2.6%, and 2.3% at the concentration of 1.0 ng mL-1 for AFP, CEA, and human IgG, respectively. The present detection method permits detecting multiple analytes from each spot of microarray with a spatial resolution at micrometer range, which can alleviate the stress to fabricate high-density arrays. Furthermore, the substrate materials and immobilized proteins do not interfere with the detection. The present technique provides a new strategy for readout of microarray. [ABSTRACT FROM AUTHOR]

Monodisperse wurtzite-type ZnS microspheres have been prepared by using glutathione (GSH) as a sulfur source at low reaction temperatures ranging from 160 to 210 °C. The diameter of the ZnS microspheres can be tuned from ~254 to ~597 nm by changing the reaction parameters such as temperature, molar ratio of reactants (GSH/Zn2+), and reaction medium (ethylenediamine or ammonia). Our results demonstrate that monodentate amines (ammonia) play the same role as that of bidentate amines (ethylenediamine) in the formation of the wurtzite-type ZnS microspheres. The formation process of the monodisperse ZnS microspheres consists of a GSH-dominated nucleation process and an amine-dominated assembly process. The as-synthesized monodisperse ZnS microspheres readily self-assemble into ordered hexagonal patterns and thus have potential applications as colloidal crystalline materials. Blue fluorescence emission peaks at 415 and 466 nm in wavelength, attributed to deep-trap emission, are observed at room temperature. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of semiconductor nanocrystals of PbSthrough a facile and inexpensive synthetic route between lead acetate[Pb(Ac)23H2O] anddithioglycol (HSCH2CH2SH) without any surfactant. The products were characterized by x-ray diffraction (XRD),transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Ramanspectroscopy, x-ray photelectron spectroscopy (XPS) and infrared (IR) spectroscopy. Thesize of cube-shaped PbS nanocrystals can be controlled by changing the relative amount ofPb(Ac)23H2O and dithioglycol. Smaller cube-shaped PbS nanocrystals were obtained at higher sulfurcontent in the reaction system. The nanometre-sized single crystals of PbS measure∼83nm 59nm 22nm and 39nm 10nm 7nm, for lead acetate:dithioglycol ratios of 1:0.375 (denoted as PbS-1) and1:1.5 (denoted as PbS-2), respectively, when a mixture of NaOH solutionof lead acetate and ethyl alcohol solution of dithioglycol is maintained at220 C for 4h in a Teflon-lined autoclave. XRD patterns and HRTEM images confirm thecrystalline structure of the PbS crystals. TEM helped to determine the dimension of thesingle crystals. Raman, XPS and IR helped to further demonstrate the purity of theas-synthesized samples. The optical absorption spectra of suspensions of the thesecrystals in glycol show shifts in absorption band edge for as-prepared sample PbS-1from 246 to 271nm and for PbS-2 from 246 to 275nm, after four days of storage,respectively. The photoluminescence peaks from the two samples are located at 434 and433nm for photoexcitation radiation of 315–355nm, thus exhibiting a Stokes shiftcompared with band edge energy. The principal contribution of this work is that thenanometre-size PbS single crystals are prepared without using a surfactant ortemplating agent. The formation of a five-membered ring via the chelation between thePb2+ ion and dithioglycol is considered to be crucial in this mechanism. [ABSTRACT FROM AUTHOR]

This paper reports wurtzite-type CdS nanostructures synthesized via a hydrothermal reaction route using dithiol glycol as the sulfur source. The reaction time was found to play an important role in the shape of the CdS nanocrystals: from dots to wires via an oriented attachment mechanism. This work has enabled us to generate nanostructures with controllable geometric shapes and structures and thus optical properties. The CdS nanostructures show a hexagonal wurtzite phase confirmed by X-ray diffraction and show no evidence for a mixed phase of cubic symmetry. The Raman peak position of the characteristic first-order longitudinal optical phonon mode does not change greatly, and the corresponding full width at half-maximum is found to decrease with the CdS shape, changing from nanoparticles to nanowires because of crystalline quality improvement. The photoluminescence measurements indicate tunable optical properties just through a change in the shape of the CdS nanocrystals; i.e., CdS nanoparticles show a band-edge emission at ∼426 nm in wavelength, while the CdS nanowires show a band-edge emission at ∼426 nm as well as a weaker trap-state green emission at ∼530 nm in wavelength. These samples provide an opportunity for the study of the evolution of crystal growth and optical properties, with the shape of the nanocrystals varying from nearly spherical particles to wires. [ABSTRACT FROM AUTHOR]

This paper describes a novel hydride atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma. The plasma was generated with a 3700-V, 20.3-kHz, and 5-W electrical power supply and easily sustained with inert gases (He or Ar) at a flow rate of 250 mL.min-1 after optimization. However, it cannot be sustained with N2. This atomizer offers the advantages of low operation temperature and low power consumption in comparison with the currently used electrothermal quartz atomization operated at 900 °C with a power supply of several hundred watts. To confirm the utility of the proposed atomizer, four arsenic species (As(III), As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA)) were determined by the present atomization technique. A hyphenation of HPLC coupled to hydride generation MS with the optimized DBD atomizer has been successfully used for the speciation of arsenic in order to demonstrate the potential of this atomizer in the present study. The characteristics of the DBD atomizer and the effects of different parameters (discharge gas, gas flow rate, voltage, HCI concentration, KBH4 concentration) are discussed in the paper. Compared with other hydride atomization techniques, the proposed method shows the following features: (1) small size (70 mm x 15 mm x 5 mm), which is preferable for the miniaturization of the total analytical system; (2) low power consumption (⩽ 5W), which indicates the possibility of the development of portable, fieldable analytical instrumentation for in situ detection using battery as power supply; (3) low atomizer temperature (∼70 °C), which is in favor of the compactness of the total instruments; (4) avoidance of residue moisture removal in comparison with the existed GD system, which leads to the facility of the system. The analytical figures of the present technique were evaluated. The detection limits of As(III), As(V), MMA, and DMA obtained with HG-DBD-AAS were 1.0, 11.8, 2.0, and 18.0 μg.L-1, respectively. The accuracy of the system was verified by the determination of arsenic in reference material of orchard leaves SRM 1571. The concentration of As determined by the present method agreed well with the reference values. The speciation of arsenic in the freeze-dried urine SRM 2670 were carried out, and the results obtained were in agreement with the results of HPLC-ICPMS and the reported values by other laboratories. [ABSTRACT FROM AUTHOR]

A novel aerosol chemiluminescent (CL) detector coupling to capillary electrophoresis (CE) for the detection of saccharides is reported. This CL detector is composed of a postcapillary nebulizer and porous alumina as catalyzer in quartz tube. The CL emission could be generated due to the catalyzing oxidization of saccharides on the surface of porous alumina. The saccharides such as sucrose, α-lactose, maltose, raffinose, galactose, xylose, and glucose with only weak UV absorbance can be successfully detected. The linear ranges of those saccharides are from 30-2000 to 50-2000 mg/L; relative standard deviations range from 2.1 to 3.7% (200 mg/L, n = 11). Compared with the traditional UV detector currently used in CE, this novel detector shows the advantage of high sensitivity to the compounds with only weak UV absorption. Thus, it could be an important supplement of CE detectors for UV- lacking compounds. [ABSTRACT FROM AUTHOR]

Proposes a gas-sensing mode based on chemiluminescence generated on the surface of nanosized titanium dioxide (TiO[sub 2]). Detection of chemiluminescence in the nanosized materials; Characteristics of ethanol and acetone vapors passing through the surface of TiO[sub 2]; Removal of carbon deposited on TiO[sub 2] by controlling the temperature.

Describes the study of atomization of nanoparticles using inductively coupled plasma mass spectrometry (ICPMS). Sensitivity of the gold signal to the organic matrix; Correlation between the method and enzyme-linked immunosorbent assay; Advantages of ICPMS-based nonisotopic immunoassay method for the determination of biologic analytes.

A novel method has been proposed to enhance efficiency of cataluminescence reaction by applying a plasma-assisted cataluminescence (PA-CFL) system. The obtained results clearly indicated that the PA-CFL system exhibited substantially higher sensitivity for the detection of benzene, toluene, ethylbenzene, and xylenes (BTEX) on the surface of nanosized ZrO2. There are two distinctive advantages in the PA-CFL system; on one hand, the plasma activates the BTEX molecules for the detection, and on the other hand, the worldng temperature range of the catalytic reaction is lowered with the plasma assistance. A detection limit (LOU = 3σ) of 20 ng mL-1 was achieved for benzene in air samples. Using a graphite electrode in the designed plasma provides an additional opportunity for solid-phase microexfraclion (SPME) sampling of volatile organic compounds (VOCs) on its surface followed by PA-CFL detection. This ability has been investigated for detection of m-xylene in air samples. [ABSTRACT FROM AUTHOR]

A simple fabrication of two-dimensional zinc sulfide colloidal arrays with the assistance of a multihydroxy polymer is described, which can potentially be utilized in different technological fields, such as biosensor and electrooptical devices as well as a platform for studies of energy transfer between colloidal particles. [ABSTRACT FROM AUTHOR]

The article reports on a study for evaluating and screening catalysts based on the chemiluminescence (CL) performance of catalytic reactions. Researchers evaluated the CL responses of carbon-monoxide (CO) oxidation on oxide-supported gold catalysts and correlated the CL features with the catalytic activity for the CO conversion, which enabled the development of a new CL-based imaging method for indication of the feasibility of a simple, rapid, and parallel screening for the catalytic activity.