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With an aging population, late-life depression has been a major health problem in rural China. This study aims to explore the gender-specific prevalence of geriatric depression in rural Tianjin, its influencing factors, and to provide a scientific basis for the prevention and intervention of depression in the elderly.A cross-sectional study of 4,933 elderly individuals in rural Tianjin was conducted using the cluster sampling method. The independent samples t-test and chi-squared test were used to assess differences in participants' characteristics by depressive symptoms, while multiple linear regressions and multiple logistic regressions were used to analyze the potential influencing factors of depression.The prevalence of geriatric depression was found to be 12.2% in the study participants (9.5% in men and 14.5% in women). Gender, education, household income, employment, living alone, social activities, physical exercise and chronic diseases were associated with depression (P0.05). In addition to the above factors, sleep duration was also related with scores on self-rating depression scale (P0.05).The study used a cross-sectional approach, so causation cannot be concluded.Late-life depression is a serious mental health issue in rural China, highlighting the importance of appropriate diagnosis and treatment as a priority to improve the quality of mental health.

This article describes a theory unifying the unusual performance of the undercoordinated adatoms, point defects, terrace edges, surfaces, and nanostructures of various shapes. The ideas of bond order-length-strength correlation and the associated nonbonding electron polarization (BOLS-NEP) feature that bonds between undercoordinated atoms contract spontaneously. Bond contraction raises the local density of charge and energy. Bond strength gain deepens the interatomic potential well to trap the core and bonding electrons deeply. In turn, the locally and densely entrapped electrons polarize those partially occupying the valence band and above pertaining to the lower-coordinated atoms. The BOLS-NEP theory reconciles the unusual behaviors of undercoordinated systems and the size dependency of nanostructures in their lattice oscillating dynamics, mechanical strength, thermal stability, photon emissivity, chemical reactivity, dielectric permeability, associated with generation of polarized Dirac fermions, serving as carriers for extraordinary catalysis, hydrophobicity, fluidity, lubricity, as well as monolayer high-TC superconductivity and topological insulator conductivity.

Photocatalytic efficiency of graphitic carbon nitride (g–C3N4) has been hindered by fast carrier recombination and high reaction energy barriers, which can be improved by combining a semiconductor with a large work function. Based on this strategy, we synthesized a novel Pt/t–ZrO2/g–C3N4 composite by integrating g–C3N4 with tetragonal ZrO2 and Pt nanoparticles. Results of experimental measurements and density functional theory simulation demonstrate that the carrier lifetime, transferability and energy barriers of catalysts depend on their work function. The optimal composite exhibits an extraordinary catalytic ability for hydrogen generation of 722.5 μmol(gh)−1 and solar–to–hydrogen energy conversion efficiency of 0.215% under visible–light irradiation, and high catalytic stability. The modification strategy could be applied to designing various different high–efficient catalysts by selecting semiconductors with suitable work functions. This work was supported in part by the Natural Science Foundation of Zhejiang Province, China (LY18E020007, LQ18E030005 and LY19F020006). Computational resources were provided by the Jilin University.

Overdosing of Na(Cl, C5H8NO4) can raise one's blood pressure but moderately intaking of C6H8O6 ascorbic and C2H4O2 acetic acids effects contrastingly with mechanisms yet to be clear. From the perspective of hydrogen bond (O:H O or HB with “:” being electron lone pairs of oxygen) cooperativity, we show phonon-spectrometrically that solvation of the Na-based doses raises their solution surface tension by ionic polarization, but solvation of the organic acids performs contrastingly by dipolar fragilization. The Na-based doses dissolve into Na+ cations and anions that serve each as a charge center to cluster, stretch, and polarize the solvent O:H O bonds, raising the viscosity of the solution. However, the acidic dipoles break the solvation network into small fragments, helping to the blood flowing. Findings could offer workable mechanisms for hypertension medication and prevention.

Development of noninvasive, reliable biomarkers for lung cancer diagnosis has many clinical benefits knowing that most of lung cancer patients are diagnosed at the late stage. For this purpose, we conducted proteomic analyses of 231 human urine samples in healthy individuals (n = 33), benign pulmonary diseases (n = 40), lung cancer (n = 33), bladder cancer (n = 17), cervical cancer (n = 25), colorectal cancer (n = 22), esophageal cancer (n = 14), and gastric cancer (n = 47) patients collected from multiple medical centers. By random forest modeling, we nominated a list of urine proteins that could separate lung cancers from other cases. With a feature selection algorithm, we selected a panel of five urinary biomarkers (FTL: Ferritin light chain; MAPK1IP1L: Mitogen-Activated Protein Kinase 1 Interacting Protein 1 Like; FGB: Fibrinogen Beta Chain; RAB33B: RAB33B, Member RAS Oncogene Family; RAB15: RAB15, Member RAS Oncogene Family) and established a combinatorial model that can correctly classify the majority of lung cancer cases both in the training set (n = 46) and the test sets (n = 14–47 per set) with an AUC ranging from 0.8747 to 0.9853. A combination of five urinary biomarkers not only discriminates lung cancer patients from control groups but also differentiates lung cancer from other common tumors. The biomarker panel and the predictive model, when validated by more samples in a multi-center setting, may be used as an auxiliary diagnostic tool along with imaging technology for lung cancer detection., Highlights • A case-control study of biomarker discovery for lung cancer diagnosis was conducted. • Human urine profiles in control cases and cancers were characterized. • A list of candidate biomarkers was nominated and evaluated. • A panel of urinary biomarkers was established and tumor-specificity was evaluated. Cancer diagnosis with a noninvasive method at the early stage of the disease is highly desirable. Here, we analyzed hundreds of human urine samples from healthy individuals, patients with benign pulmonary diseases, and 6 types of cancers by proteomics and developed a panel of five urinary proteins that can separate the lung cancer from benign pulmonary diseases as well as the other 5 cancers (bladder, cervical, colorectal, esophageal and gastric) with a good sensitivity and disease specificity. Further validation experiments with expanded sample numbers are required to investigate whether this method can be applied in a clinical setting for the diagnosis of lung cancer.

This study aimed to examine the effects of different types of bullying victimization (direct, relational, and cyber) on psychological symptoms, self-harm, and suicidality (including suicidal ideation and attempts) among adolescents, and to explore whether these effects may vary by gender. The data were obtained from a cross-sectional study of adolescents (n = 11,248, 46.7% females) with a mean age of 13.83 years from grade 5 to 12 in Henan, China. A series of binary logistic regression models were conducted to estimate the associations between different types of bullying victimization and psychological symptoms, self-harm, suicidal ideation, and suicidal attempts, after adjusting for demographic covariates. All three types of bullying victimization were significantly associated with psychological symptoms, self-harm, suicidal ideation, and suicidal attempts. Adolescents who suffered from cyberbullying victimization were more likely to commit self-harm and suicidal attempts as compared to direct and relational victimization. Female adolescents who suffered from relational bullying tend to have a higher risk of suicidal attempts than male adolescents. The current study demonstrated the negative effect of bullying victimization on adolescents’ adverse psychological outcomes and gender difference need to be taken into account in developing targeted intervention strategies to address bullying victimization.

By studying the tantalum (Ta)(111) surface with X-ray photoemission spectroscopy and density functional theory, we determined binding energy values for the clean Ta(111) (+3.068 eV) and hydrogenated Ta(111) (+3.421 eV) surfaces with an isolated atom level of 18.977 eV. Using the bond–band barrier and zone-selective electron spectroscopy correlation, we investigated the mechanism of hydrogenation adsorption on the Ta(111) surface. We found the local densities of states of the first layer of Ta atoms in the reconstructed structure, which formed on the adsorbent hydrogen of the surface chemical bond contracts and dipole polarization. Moreover, we showed that on the Ta(111) surface, the hydrogen-induced surface core level shifts are dominated by quantum entrapment and are proportional to the calculated hybridized orbitals of the valence band. The latter is therefore correlated to the local surface chemical reactivity and is useful for other adsorbate systems on transition metals.

In the present study, we present a new Pn anisotropic tomographic model of the uppermost mantle underneath the South China Sea and surrounding areas through the inversion of 23,042 high-quality hand-picked Pn arrival-time data. Our model shows obvious lateral heterogeneities in velocity and anisotropy that are closely correlated to surface geological structure in the study region. High Pn velocity anomalies are generally observed in the structurally stable areas, such as the South China block and Pearl-River Mouth basin. Obvious low Pn velocity anomalies are imaged underneath the Tengchong volcano, the Hainan volcano, and other volcanoes along the Ryukyu, Luzon, Philippine, and Java arcs, whereas the low-to-high-velocity transition zone is visible underneath the volcanoes in the Sumatra arc. Most large crustal earthquakes occurred in the low Pn velocity areas in the Ryukyu, Luzon, and Philippine arcs and the low-to-high Pn velocity transition zones in the Sumatra and Java arcs. These results suggest that these volcanism and earthquake occurrences may be closely related to the deep dynamics of the subduction of the Philippine Sea and Australian plates. High Pn velocity areas with trench-perpendicular fast directions of Pn propagation are revealed in the Ryukyu, Philippine, Sumatra, and Java trenches, presenting the subducting Philippine Sea and Australian plates, whereas low Pn velocity areas with trench-parallel fast directions are visible in the arc areas, suggesting the compressed mantle flows there. Our results provide new seismological evidence for understanding the mantle dynamics beneath the South China Sea and surrounding areas.

Unlike most social programs that involve regular delivery of benefits (such as subsidized food or monthly cash transfers), public health insurance programs are used based on need. When households face health shocks, they are often unaware of how to avail health insurance benefits. This is especially true for households in remote rural regions of developing countries where the likelihood of low awareness about public health insurance programs is higher due to low levels of literacy, distance from healthcare facilities and limited opportunities to learn from others’ experiences. Conventional information, education and communication (IEC) methods such as information pamphlets and outreach through health camps are not always effective in disseminating information to these hard-to-reach populations. In this paper, we present results from a quasi-experiment that uses village-level awareness meetings to disseminate information about a public health insurance program in 61 villages of a district in southern India. We find that awareness meetings, though relatively more expensive than conventional IEC methods, not only increase utilization of the program but also provide government agencies a unique opportunity to monitor the implementation of the program in remote locations.

MoSe 2 -TiO 2 composites were successfully synthesized via a facile solvothermal method. Their morphology, structure and photocatalytic activity in the reduction of Cr(VI) were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectra, respectively. The results show that the introduction of TiO 2 into MoSe 2 boosts the light harvesting efficiency and charge separation and transfer due to their synergistic effect, thus enhancing the visible light photocatalytic activity of MoSe 2 with a maximum Cr(VI) reduction rate of 91% at 120 min compared with pure MoSe 2 (61%) and TiO 2 (5%).

We perform a finite-frequency tomographic inversion to image 3D velocity structures beneath southern and central Tibet using teleseismic body-wave data recorded by the TIBET-31N passive seismic array as well as waveforms from previous temporary seismic arrays. High-velocity bodies dip ∼40° northward beneath the Himalaya and the Lhasa Terrane. We interpret these high-velocity anomalies as subducting Indian Continental Lithosphere (ICL). The ICL appears to extend further north in central Tibet than in eastern Tibet, reaching 350 km depth at ∼31°N along 85°E but at ∼30°N along 91°E. Low P- and S-wave velocity anomalies extend from the lower crust to ≥180 km depth beneath the Tangra Yum Co Rift, Yadong-Gulu Rift, and the Cona Rift, suggesting that rifting in southern Tibet may involve the entire lithosphere. The anomaly beneath Tangra Yum Co Rift extends down to about 180 km, whereas the anomalies west of the Yadong-Gulu Rift and east of the Cona Rift extend to more than 300 km depth. The low-velocity upper mantle west of the Yadong-Gulu Rift extends furthest north and appears to connect with the extensive upper-mantle low-velocity region beneath central Tibet. Thus the northward-subducting Indian Plate is fragmented along north–south breaks that permit or induce asthenospheric upwellings indistinguishable from the upper mantle of northern Tibet.

Lycopene, a natural carotenoid, has potential chemopreventive effects in many cancers. This study aimed to examine the effects of lycopene on regulating the inflammation and apoptosis of N-nitrosomethylbenzylamine(NMBzA) induced esophageal cancer in F344 rats. After the rats were fed normal diets containing different concentrations of lycopene for 25 weeks (10, 25, 50 mg/kg·d of lycopene, respectively), the incidence of tumors in the rats treated with lycopene was significantly lower than that in the simple exposed group (P

Genomic studies of lung adenocarcinoma (LUAD) have advanced our understanding of the disease's biology and accelerated targeted therapy. However, the proteomic characteristics of LUAD remain poorly understood. We carried out a comprehensive proteomics analysis of 103 cases of LUAD in Chinese patients. Integrative analysis of proteome, phosphoproteome, transcriptome, and whole-exome sequencing data revealed cancer-associated characteristics, such as tumor-associated protein variants, distinct proteomics features, and clinical outcomes in patients at an early stage or with EGFR and TP53 mutations. Proteome-based stratification of LUAD revealed three subtypes (S-I, S-II, and S-III) related to different clinical and molecular features. Further, we nominated potential drug targets and validated the plasma protein level of HSP 90β as a potential prognostic biomarker for LUAD in an independent cohort. Our integrative proteomics analysis enables a more comprehensive understanding of the molecular landscape of LUAD and offers an opportunity for more precise diagnosis and treatment.

Mitochondria DNA was preferentially attacked by the exogenous carcinogens including polycyclic aromatic hydrocarbons (PAHs) relative to nuclear DNA, and nuclear gene variants may account for variability in the mitochondrial DNA copy number (mtDNAcn). However, it remains unclear whether miRNA genetic variations are associated with mitochondrial DNA damage in the PAH-exposed workers. Therefore, we measured the leukocyte mtDNAcn, urinary 1-hydroxypyrene (1-OHPYR), environmental PAH exposure, and miRNA genetic polymorphisms among 544 coke oven workers and 238 healthy control participants. We found that the mtDNAcn in the exposure group (0.60 ± 0.29) was significantly lower than that in the control group (1.03 ± 0.31) (t = 18.931, P 0.001). Spearman correlation analysis showed that the peripheral blood leukocyte mtDNAcn had significantly negative correlations with the levels of 1-OHPYR and environmental PAH exposure (P 0.001). Covariance analysis indicated that miR-210 rs11246190 AA, miR-210 rs7395206 CC, and miR-126 rs2297538 GG probably promoted a decrease in leukocyte mtDNAcn in the exposure or control groups (P 0.05). In generalized linear model, miR-210 rs11246190 GG was a protective factor of mtDNAcn, and environmental PAH exposure was the risk factor of the mtDNAcn. In conclusion, the decrease of leukocyte mtDNAcn is the result of a combination of environmental and genetic factors.

a b s t r a c t West-east extension is a prominent tectonic feature of southern and central Tibet despite ongoing north- south (N-S) convergence between India and Eurasia. Knowledge of deep structure beneath the N-S trending rifts is key to evaluating models proposed for their origin, including gravitational collapse, oblique convergence along the arcuate plate boundary, and mantle upwelling. We model direct S and Moho-reflected SsPmp phases at teleseismic distances to constrain variations in crustal thickness across the major rifts crossed by a ∼900-km long, W-E broadband array in the Lhasa Terrane. Crustal thicknesses are ∼70-80 km. However, Moho depth decreases by ∼10 km within a horizontal distance of 100 km west of the Yadong-Gulu rift (YGR) and Nyainquentanghla mountains (NQTL). This Moho uplift, taken with deep, extensional focal mechanisms and reduced seismic velocity in the upper mantle, suggests that asthenospheric upwelling has significantly contributed to the pattern of extension across the YGR and NQTL. The ∼100-km separation between surface rift and Moho uplift is likely enabled by partial decoupling across a ductile middle crust. © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Numerical reproduction of the measured 4f7/2 energy shift of Ir(1 0 0), (1 1 1), and (2 1 0) solid skins turns out the following: (i) the 4f7/2 level of an isolated Ir atom shifts from 56.367 eV to 60.332 eV by 3.965 eV upon bulk formation; (ii) the local energy density increases by up to 130% and the atomic cohesive energy decreases by 70% in the skin region compared with the bulk values. Numerical match to observation of the temperature dependent energy shift derives the Debye temperature that varies from 285.2 K (Surface) to 315.2 K (Bulk). We clarified that the shorter and stronger bonds between under-coordinated atoms cause local densification and quantum entrapment of electron binding energy, which perturbs the Hamiltonian and the core shifts in the skin region.

A series of TiO2-reduced graphene oxide (RGO) nanocomposites were prepared by a green one-pot hydrothermal reactions using P25 as the titania precursor and graphene oxide (GO). Our method provides the notable advantages of a one-step reaction without employing toxic solvents, thereby providing a green, simple and quick synthetic route to produce TiO2-RGO nanocomposites. The synthesized nanocomposites showed enhanced photocatalytic activity compared to P25 under UV-vis illumination, it even can degrade the Rhodamine (Rh) B in the dark conditions. (C) 2014 Elsevier B.V. All rights reserved.

The mechanism of the crustal deformation at different depths under the eastern Tibetan Plateau is still unresolved. In this study, we conduct shear-wave splitting measurements using two-frequency bands (0.08–0.6 Hz and 0.6–1.0 Hz) Moho-converted Pms receiver-function analyses of teleseismic events recorded at 29 temporary seismic stations densely and linearly deployed across the Longmenshan thrust belt. Our results show that the average delay time between the fast and slow shear waves is ~0.37 s at the high-frequency band, which is smaller than ~0.49 s at the low-frequency band. The fast polarization directions are consistent beneath the Songpan-Ganzi Block between the high- and low-frequency bands, but they are much more heterogeneous at the high-frequency band than those at the low-frequency band beneath the Longmenshan thrust belt and the western Sichuan Basin. The dominated fast polarization direction at the high-frequency band, consistent with the strike of active faults on the surface, possibly reflects the upper crustal deformation, whereas at the low-frequency band it may reflect the lower crustal deformation. All these results suggest that the deformation between the upper and lower crust beneath the Songpan-Ganzi Block could be coupled, but it might be decoupled beneath the Longmenshan thrust belt and the western Sichuan Basin.

To investigate the deep origin of Cenozoic intraplate volcanism in Northeast (NE) China, especially the Wudalianchi volcanism, a new 3-D S-wave velocity model of the crust and uppermost mantle is constructed through ambient noise tomography. Rayleigh wave phase velocity dispersion curves of 5–40 s periods are collected from seismograms recorded at our newly deployed WAVESArray portable stations around the Wudalianchi volcano and NECESSArray portable stations and CEA provincial seismic stations in NE China. Compared to images resolved in previous studies, the addition of WAVESArray data provides much higher resolution in NE China. Under the Songliao, Erlian and Hailar basins, obvious low-velocity (low-V) anomalies are imaged above 5 km depth, which are well correlated with the sediments and have good correlations with the outlines of the basins. Under the Changbaishan volcano and Abaga and Halaha volcanic groups, low-V anomalies extend continuously down to the uppermost mantle, suggesting their continuous mantle magma provision. Under the Wudalianchi volcano, low-V anomalies above 20 km depth and in the upper mantle are revealed, but a high-velocity anomaly zone appears in the lower crust, suggesting that the Wudalianchi volcano is a type of mantle origin but parts of magma have been solidified in the lower crust, likely due to intermittent mantle magma provision. All these results indicate that the intraplate volcanism in NE China could be related to complicated mantle dynamics of the big mantle wedge that has been formed due to the stagnancy and dehydration of the subducted Pacific slab in the mantle transition zone.

The deformation and breaking behaviors of metallic nanowires have raised concerns owing to their applied reliability in a nanoelectromechanical system. In this paper, molecular dynamics simulations are used to study the deformation and breaking properties of the [1 0 0] oriented single-crystal copper nanowires subjected to uniaxial tension at different temperatures. With a dependence of temperature, statistical samples identify a most probable breaking position of the nanowire, and the “most probable” feature reveals that the breaking behavior is correlated with nanoscale compression wave propagation at different temperatures. Macro-breaking position distributions confirm the influence of temperature on micro-atomic fluctuation during the symmetric stretching of the nanowires.

a b s t r a c t We present an approach for quantifying the heterogeneous interface bond energy using X-ray photo- electron spectroscopy (XPS). Firstly, from analyzing the XPS core-level shift of the elemental surfaces we obtained the energy levels of an isolated atom and their bulk shifts of the constituent elements for ref- erence; then we measured the energy shifts of the specific energy levels upon interface alloy formation. Subtracting the referential spectrum from that collected from the alloy, we can distil the interface effect on the binding energy. Calibrated based on the energy levels and their bulk shifts derived from elemental surfaces, we can derive the bond energy, energy density, atomic cohesive energy, and free energy at the interface region. This approach has enabled us to clarify the dominance of quantum entrapment at CuPd interface and the dominance of polarization at AgPd and BeW interfaces, as the origin of interface energy change. Developed approach not only enhances the power of XPS but also enables the quantification of the interface energy at the atomic scale that has been an issue of long challenge.

ZnO–TiO 2 –carbon nanotubes (CNTs) composites are successfully synthesized using microwave-assisted reaction of ZnO precursor in TiO 2 and CNTs suspension using a microwave synthesis system and they are used as photocatalysts for photocatalytic reduction of Cr(VI). The results show that the CNTs addition could enhance the photocatalytic performance of ZnO–TiO 2 composites. The ZnO–TiO 2 composites achieve a maximum reduction rate of 90% at 240 min under UV light irradiation, much higher than those for the pure ZnO (58%) and the ZnO–TiO 2 (69%). The improvement is ascribed to the increased light absorption intensity and range as well as the reduction of electron–hole pair recombination with the introduction of CNTs.

Monte Carlo simulation of the order–disorder transition revealed that the transition temperature of Co–Pt nanowires increases with wire diameter, approaching the bulk value if the size is large enough. The transition temperature is affected by the shape of cross-section, though the shape effect is less significant than the size effect. It is showed that the rise of transition temperature in nanowires is largely due to the decrease of surface area compared with nanoparticles. The phase separation and tetragonalization are discussed by introducing mixing parameter and asphericity parameter. It is also found that the order–disorder transition starts from the surface and then to the core, indicating that the order–disorder transition of nanowires is a surface-dominant phenomenon, governed by the atomic under coordination.

We examined the ac transport attribute of the multi-terminal structures in the absence and presence of magnetic field. We found that the ac response depends on the structural configurations and that the admittance varies with the features of the attached nanoribbons. In the vicinity of Dirac point the dc conductance manifests a dip or peak and the imaginary part (emittance) vanishes or not, depending on whether the attached ribbon is semiconductive or metallic. In the presence of magnetic field, the emittance becomes asymmetric reflecting the dynamic behaviors of electron and hole.

a b s t r a c t ZnO-reduced graphene oxide (RGO) composites are successfully synthesized via UV-assisted photocat- alytic reduction of graphite oxide by ZnO nanoparticles in ethanol. Their morphology, structure and photocatalytic performance in reduction of Cr(VI) are characterized by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray diffraction spectroscopy, UV-vis absorption spectrophotometer, respectively. The results show that in the composites the RGO nanosheets are decorated densely by ZnO nanoparticles, which displays a good combination between RGO and ZnO. ZnO-RGO composites exhibit an enhanced photocatalytic performance in reduction of Cr(VI) with a maxi- mum removal rate of 96% under UV light irradiation as compared with pure ZnO (67%) due to the increased light absorption intensity and range as well as the reduction of electron-hole pair recombination in ZnO with the introduction of RGO.

We have explored the effects of atoms under-coordination on surface structure relaxation, binding energy shift of W stepped surfaces and valence charge polarization by the method of incorporating bond order-length-strength (BOLS) correlation mechanism into high-resolution X-ray photoluminescence spectra (XPS) measurements as well as density functional theory (DFT) calculations. Results show that the 4f7/2 energy levels of bulk, surface skin and step edge W atoms shift deeper from 2.17 to 2.69 eV with respect to that of the isolated W (28.91±0.01 eV) atoms, while the valence charge energy shift upper from inner to outer layer and from bulk to stepped edge. The surface bond contraction occurs around under-coordinated atoms after geometry relaxation calculation. Consistency among BOLS calculations, DFT calculation and experimental measurements clarifies that the surface bond contraction and consolidation due to the effects of under-coordination atoms induce potential trap depression, which provides perturbation to the Hamiltonian and hence contributes to the surface core level shift deeper, and that the surface valence charge are polarized by the densely trapped core-level electrons to upper energy.

Atomistic simulations are used to investigate the mechanical properties of copper nanowires (NWs) along 〈1 0 0〉, 〈1 1 0〉 and 〈1 1 1〉 crystallographic orientations under tensile loading at different temperatures. The inter-atomic interactions are represented by employing embedded-atom potential. To identify the defects evolution and deformation mechanism, a centrosymmetry parameter is defined and implemented in the self-developed program. The simulations show that Cu NWs in different crystallographic orientations behave differently in elongation deformations. The stress–strain responses are followed by a particular discussion on yield mechanism of NWs from the standpoint of dislocation moving. Generally, the study on the incipient plastic deformation will be helpful to further understanding of the mechanical properties of nanomaterials. In addition, the Young’s modulus decreased linearly with the increase of temperature. The crystal structure is less stable at elevated temperatures.

Sensitized-type solar cells based on ZnO photoanode and CdS quantum dots (QDs) as sensitizers have been fabricated. Both ZnO films and CdS QDs are prepared using ultrasonic spray pyrolysis (USP) deposition technique. This method allows a facile and rapid deposition and integration between CdS QDs and ZnO films without the need for post thermal treatment. The photovoltaic performances of the cells are investigated. The results show that the performance of the cell based on all USP deposited CdS sensitized ZnO photoanode achieves maximally a short circuit current density of 6.99 mA cm−2 and a power conversion efficiency of 1.54%.

The carbon nanotubes and carbon nanofibers composite films (CNTs-CNFs) were fabricated by chemical vapor deposition. The electrosorption performance of CNTs-CNFs films at different solution temperatures was studied. It is found that the salt removal decreases from 45.4% to 33% due to hydrophobic-hydrophilic transition taking place on the surface of CNTs-CNFs films, when solution temperature ranges from 281 to 295 K. The electrosorption isotherm investigation shows Langmuir isotherm can better describe experimental data. Meanwhile, the kinetics and thermodynamics analyses indicate that the electrosorption of NaCl onto CNTs-CNFs electrodes follows first-order kinetics model and is driven by a physisorption process. Refereed/Peer-reviewed

article i nfo Carbon nanotube (CNT)-zinc oxide (ZnO) nanocomposite and gel poly(vinyl alcohol)-phosphomolybdic acid were employed as the electrode and electrolyte of the experimental supercapacitor cell, respectively. The ZnO nanodots were deposited onto CNT films by ultrasonic spray pyrolysis in different times. The results of electrochemical measurements showed that the electrode with ZnO deposited in 5min had the optimal capacitive properties among the experimental series, with a lowest interfacial electron transfer resistance, a very high capacitance of 323.9 F/g and good reversibility in the repetitive charge/discharge cycling test. © 2009 Elsevier B.V. All rights reserved.

A novel amperometric sensor for the determination of sulfite was fabricated based on multiwalled carbon nanotubes (MWCNTs)/ferrocene-branched chitosan (CHIT-Fc) composites-covered glassy carbon electrode (GCE). The electrochemical behavior of the sensor was investigated in detail by cyclic voltammetry. The apparent surface electron transfer rate constant (K(s)) and charge transfer coefficient (alpha) of the CHIT-Fc/MWCNTs/GCE were also determined by cyclic voltammetry, which were about 1.93 cm s(-1) and 0.42, respectively. The sensor displayed good electrocatalytic activity towards the oxidation of sulfite. The peak potential for the oxidation of sulfite was lowered by at least 330 mV compared with that obtained at CHIT/MWCNTs/GCE. In optimal conditions, linear range spans the concentration of sulfite from 5 microM to 1.5mM and the detection limit was 2.8 microM at a signal-to-noise ratio of 3. The proposed method was used for the determination of sulfite in boiler water. In addition, the sensor has good stability and reproducibility.

An enzyme-free glucose sensor has been developed using a three-dimensional inverse-opal gold film electrode (3DGFE) obtained by electrochemical deposition of gold in the interspaces of polystyrene templates. The gold films were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrochemical oxidation of glucose in the presence of interferents (ascorbic acid, and so on) at different operating potentials on the 3DGFE has been investigated in detail. A low operating potential of −0.30 V was chosen for glucose detection, since the interference could be well avoided at this potential, whereas the current response for glucose oxidation was still sensitive. The amperometric response of the sensor increased with the increase of glucose concentration with a linear range of 5 × 10−6 to 10−2 M and a detection limit of 3.2 μM (signal-to-noise ratio of 3). The glucose sensor exhibited a high sensitivity of 46.6 μA mM−1 cm−2, which could be ascribed to the unique surface structure of the three-dimensionally interconnected porous structured gold films. The sensor with high sensitivity, good selectivity and stability is attractive for the practical glucose detection.

Nanocrystalline nickel films of 17–40 nm grain sizes were prepared using pulsejet electrodeposition. Structure, corrosion and lattice strain were analysed by transmission electron microscope, electrochemical workstation and X-ray diffraction, revealing that with decreasing of grain size, the lattice strain, corrosion rate of the films are enhanced. The observations can be consistently understood in terms of the bond-order-length-strength correlation mechanism indicating that the shortened and strengthened bonds between the under-coordinated atoms modify the energy density and the atomic cohesive energy in the surface skins of the grains. The surface energy density gain is responsible for the residual atomic cohesive energy for the activation energy of corrosion. Additionally, a novel algorithm was proposed to extract the elastic-plastic properties of nickel films and results that the nickel film has much higher yield strength than bulk nickel.

We used the Langmuir–Blodgett (LB) technique to construct a well-defined and structure-controllable photochromic material—a highly ordered multilayer film composed of dioctadecylamine and 12-molybdophosphoric acid (PMo 12 ). We identified well-ordered lamellar structures using X-ray diffraction, polarized IR, and Raman spectra, and we determined a packing model of the two components in the LB film. We found the Keggin structure and fundamental features of the PMo 12 ion to be maintained in the hybrid film. This hybrid LB film displayed photochromic properties upon UV light irradiation and we observed the following process from first-order kinetics. The photochromism exhibited the ability to switch between colorless and blue. A fading process occurred when the film was exposed to ambient air or O 2 in the dark. During the color change, the packing structure of the film was well maintained. We also examined the electrochemical behavior of the hybrid LB film by cyclic voltammetry in detail and we propose different kinetic mechanisms for the film before and after irradiation.

A novel reagentless bienzymatic sensor for the determination of glucose in the low working potentials without interference is proposed. The bienzymatic sensor was fabricated by covalently attachment of periodate-oxidized glucose oxidase (IO 4 − -GOx) and horseradish peroxidase (HRP) on controlled multilayer films of sulfonate-capped gold nanoparticles/thionine (SCGNPs/TH). Using the layer-by-layer method (LBL), SCGNPs and TH were deposited alternately on the gold electrode through the electrostatic and covalent interactions. SCGNPs could greatly enhance the amount of immobilized TH and ensure the good conductivity of the whole structure. UV–vis absorption spectroscopy and electrochemical methods showed that the resulting multilayer films were tridimensional conductive and porous, and TH incorporated in LBL configuration had well electroactive performance. Such superstructures can thus provide an ideal matrix for the construction of bienzymatic sensor, where TH molecules acted as a mediator for electron transfer. After IO 4 − -GOx and HRP were covalently attached to the multilayer precursor film, the resulting biosensor exhibited good electrocatalytical response toward glucose and that the electrocatalytical response increased with the number of TH layers. This suggested that the analytical performance such as sensitivity and detection limit of the bienzymatic sensors could be tuned to the desired level by adjusting the number of deposited SCGNPs/TH bilayers. Furthermore, because of the low working potentials, the interference from other electro-oxidizable compounds (such as uric acid, ascorbic acid and acetaminophen) was avoided, which improved the selectivity of the biosensors. The biosensor constructed with six bilayers of SCGNPs/TH showed a good performance of glucose detection with a fast response less than 20 s, acceptable sensitivity of 3.8 μA mM −1 cm −2 and the detection limit of 3.5 × 10 −5 M.

Gold nanoparticles-mesoporous silica composite (GNPs-MPS) is developed as a novel enzyme immobilization matrix for biosensor construction. The mesoporous silica SBA-15 is chosen and the GNPs-SBA-15 is formed from AuCl4− adsorbed H2N-SBA-15 by NaBH4 reduction. The synthesis process of the composite is monitored by UV–vis spectroscopy and the product is characterized by transmission electron microscopy (TEM) measurement. An amperometric glucose biosensor is built by immobilizing IO4−-oxidized-glucose oxidase (IO4−-oxidized-GOD) on GNPs-MPS modified Au electrode using 2-aminoethanethiol as a cross-linker. Cyclic voltammetry (CV) and amperometry are employed to investigate the catalytic behavior of the biosensor to the oxidation of glucose. As a result, the biosensor exhibits an excellent bioelectrocatalytic response to glucose with a fast response time less than 7 s, a broad linear range of 0.02–14 mM, high sensitivity of 6.1 μA mM−1 cm−2, as well as good long-term stability and reproducibility. These performances could be ascribed to the GNPs-MPS's features, such as excellent conductivity, large surface area and good biocompatibility.

The direct electron transfer of glucose oxidase (GOD) was achieved based on the immobilization of GOD/colloidal gold nanoparticles on a glassy carbon electrode by a Nafion film. The immobilized GOD displayed a pair of well-defined and nearly reversible redox peaks with a formal potential (Eo ') of -0.434 V in 0.1 M pH 7.0 phosphate buffer solution and the response showed a surface-controlled electrode process. The dependence of Eo ' on solution pH indicated that the direct electron transfer reaction of GOD was a two-electron-transfer coupled with a two-proton-transfer reaction process. The experimental results also demonstrated that the immobilized GOD retained its electrocatalytic activity for the oxidation of glucose. So the resulting modified electrode can be used as a biosensor for detecting glucose.

Photosensitive multilayer films have been fabricated from tetra(4-carboxylphenyl)porphyrin (TCPP) and diazoresins (DAR) via H-bonding self-assembly technique. Under irradiation with UV light, following the decomposition of the diazonium group, the H-bonding in the films converts to a covalent bond. These changes had been further confirmed by UV–Vis spectra and FTIR spectra. As a consequence, the stability of the films towards polar solvents increases dramatically. From the surface photovoltage spectra (SPS), it could be followed that the photovoltage response of the n-type silicon increased remarkably when modified with 10 bilayers of TCPP/DAR multilayer films.

By using an ionic layer-by-layer self-assembly technique, the fabrication of highly stable diazo-resins/colloidal gold nanoparticles multilayer films on quartz wafer, Si slide and glassy carbon electrodes (GCEs) was achieved by the UV irradiation of layer-by-layer self-assemble multilayer films consisting of diazo-resins (DAR) and citrate-capped colloidal gold nanoparticles. UV irradiation converted the electrostatic interaction into covalent bonds at the interfaces. These fabricating processes were followed and further confirmed by UV–vis spectrometry, Fourier transform infrared spectrometer (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The obtained thin films were also characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). The results show that these assemblies of colloidal gold nanoparticles multilayer films are highly stable and can be kept for a long time, only being removed by physical scrape.

A novel amperometric sensor of hydrogen peroxide was developed based on the immobilization of myoglobin (Mb) and colloidal gold nanoparticles (CGNs) on a glassy carbon electrode (GCE) by a Nafion film. The immobilized Mb displayed a pair of well-defined and nearly reversible cyclic voltammetric peaks with a formal potential (E°′) of −0.373 V in a 0.1 M phosphate buffer solution (PBS) of pH 6.9. The formal potential of the Mb heme Fe(III)/Fe(II) couple shifted linearly with pH with a slope of −49.6 mV/pH, indicating that the electron transfer is accompanied by single-proton transportation. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide, based on which an unmediated biosensor for hydrogen peroxide was achieved. The linear range for determination of hydrogen peroxide was from 1.5 × 10−6 to 9.0 × 10−5 M with a detection limit of 5.0 × 10−7 M at a signal-to-noise ratio of 3. The stability, repeatability and selectivity of the biosensor were also evaluated.

Spherical silver nanoparticles capped by mercaptosulfonic acid with a diameter of about 8 nm were prepared by a simple chemical reaction. The resulting silver nanoparticles were characterized by UV–vis spectroscopy (UV–vis) and transmission electron microscopy (TEM). Using layer-by-layer (LBL) self-assembly technique, the multilayer films containing silver nanoparticles and polycation poly(dialyldimethylammonium chloride) (PDDA) were successfully fabricated. The fabrication process was monitored by UV–vis spectra and the morphology of the multilayer films was investigated by atomic force microscopy (AFM). The cyclic voltammogram (CV) measurements further confirmed that the silver nanoparticles had assembled into the multilayer films successfully. Surface-enhanced Raman spectroscopy (SERS) measurements showed that the multilayer films containing silver nanoparticles could serve as SERS-active substrate.

A feasible approach to construct multilayer films of glucose oxidase/gold nanoparticles on the Au electrode surface using a cysteamine as a covalent attachment cross-linker is described. The layer-by-layer covalent attachment process was followed and confirmed by electrochemical impedance spectroscopy. On the basis of the studies of UV–Vis spectroscopy and cyclic voltammetry, we demonstrated that the GOD/GNPs multilayer film was formed in a progressive and uniform manner. The CV experiments revealed that the Au electrodes modified with the GOD/GNPs multilayers exhibited an excellent bioelectrocatalytic response to the oxidation of glucose and that the bioelectrocatalytic response was directly correlated to the number of deposited bilayers, that is, to the amount of active enzyme immobilized on the Au electrode surface. The biosensor constructed with six bilayers of GOD/GNPs showed a wide linear response to glucose in the range of 1.0 × 10−5–1.3 × 10−2 M, with a fast response less than 4 s, high sensitivity of 5.72 μA mM−1 cm−2, as well as good stability and long-term life. The proposed method would be applied to the constructions of thickness and sensitivity controllable biosensing interfaces composed of multienzymes as well as a single enzyme. Keywords: Glucose oxidase, Gold nanoparticles, Biosensor, Layer-by-layer covalent attachment, Multilayered enzyme construction

A novel method to fabricate glucose biosensor was developed by immobilizing glucose oxidase (GOx) on gold nanoparticles, which had self-assembled on Au electrode modified with thiol-containing three-dimensional network of silica gel. The assembly process was followed and confirmed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which indicated that the gold nanoparticles in the biosensing interface efficiently improved the electron transfer between analyte and electrode surface. The immobilized enzyme on the electrode surface exhibits excellent catalytic activities for the oxidation of glucose when soluble redox mediator ferrocenemethanol was present. The coverage of electrically wired active GOx ( Γ E 0 ) at the enzyme electrode surface was evaluated high to be 4.5 × 10 −12 mol cm −2 on the basis of kinetic models reported in literature. Moreover, this sensor exhibited fast amperometric response (3 s) to the mediated electrocatalyzed oxidation of glucose, and the catalytic current is proportional to the concentration of glucose up to 6 mM with a high sensitivity of 8.3 μA mM −1 cm −2 . The detection limit of the sensor was estimated to be 23 μM. In addition, the sensor has good reproducibility, and can remain stable over 60 days.

A new amperometric sensor was fabricated based on the immobilization of complex of Na 2 H 6 CoW 11 Co(H 2 O)O 39 ·14H 2 O (CoW 11 Co) and poly(4-vinylpyridine) (PVP) in a TiO 2 sol–gel matrix by vapor deposition method. The preparation process simplified the traditional sol–gel process and prevented the cracking of conventional sol–gel derived glasses. The electrochemical behavior of the new amperometric sensor was studied in detail by cyclic voltammetry, and three reversible two-electron redox waves were observed in acidic aqueous solution in the potential range of −0.1 to −0.7 V. The sensor displays good electrocatalytic activity toward the reduction of bromate, iodate and hydrogen peroxide in acidic aqueous solution and the catalytic mechanisms were also discussed. The catalysis of the sensor towards bromate and iodate was systematically studied by amperometric method. The method gave a linear range from 2.0 × 10 −5 to 4.4 × 10 −3 M and a detection limit of 5.0 × 10 −6 M for BrO 3 − and 2.0 × 10 −6 to 2.8 × 10 −4 and 8.0 × 10 −7 M for IO 3 − , respectively. In addition, the sensor has some distinct advantages over the traditional polyoxometalate sensor, such as simple preparation process, fast response and long-term stability.

By using the ionic self-assembly technique, ordered multilayer thin films composed of diazo-resin (DAR) as polycation and water-soluble binuclear cobalt phthalocyaninehexasulfonate (Bi-CoPc) as polyanion were alternately fabricated on quartz, CaF2 and glassy carbon electrodes (GCEs). Upon ultraviolet irradiation, the adjacent interface of the multilayer films reacted to form a covalently cross-linking structure. The obtained thin films were characterized by ultraviolet (UV)-vis, Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), atomic force microscope (AFM), surface photovoltage spectra (SPS), and cyclic voltammetry. The results show that the uniform, highly stable and ordered multilayer thin films were formed. The linkage nature between the adjacent interface of the multilayer films converts from ionic to covalent, and, as a result, the stability of the multilayer thin films dramatically improved. The multilayer thin films on GCEs also exhibited excellent electrochemical behavior.

A novel and facile approach to construct multilayered glucose oxidase (GOx) films on the surface of quartz or CaF2 slides as well as gold electrodes for use as biosensing interfaces is described. Diazo-resins (DAR) as polycation and glucose oxidase as polyanion were alternately deposited into a multilayer structure using layer-by-layer self-assembly technique based on electrostatic interaction as driving force. Upon near UV irradiation, the adjacent interfaces of the multilayer reacted to form a crosslinking structure which greatly improved the stability of the enzyme films. These changes was monitored and confirmed by UV–vis and IR spectroscopy. Ellipsometric measurements reveal that the enzymes formed sub-molecule layers, and the thickness of the film shows a linear relationship with the number of assembled layers, demonstrating a spatially well-ordered manner in multilayer structure. The covalently attached enzyme multilayer film has a highly permeable structure, and can be used as biosensing interface. Electrochemical and analytical behavior of the enzyme electrodes was studied by cyclic voltammetry (CV) in the presence or absence of glucose. The sensitivity of the enzyme-modified electrodes was estimated through the analysis of voltammetric signals, which can be fine turned to the desired level by adjusting the number of attached bilayers.