Atomic layer deposition to heterostructures for application in gas sensors

Atomic layer deposition(ALD) is a versatile technique to deposit metals and metal oxide sensing materials at the atomic scale to achieve improved sensor functions. This article reviews metals and metal oxide semiconductor(MOS) heterostructures for gas sensing applications in which at least one of the preparation steps is carried out by ALD. In particular, three types of MOS-based heterostructures synthesized by ALD are discussed, including ALD of metal catalysts on MOS, ALD of metal oxides on MOS and MOS core–shell(C–S) heterostructures.The gas sensing performances of these heterostructures are carefully analyzed and discussed.Finally, the further developments required and the challenges faced by ALD for the synthesis of MOS gas sensing materials are discussed.

Soft-Chemical Synthesis of Vanadium Oxide Nanostructures Using 3,3’,3”-Nitrilotripropionic Acid(NTP)as a Carrier

Vanadium oxide nanostructures were synthesized using NTP as a carrier through soft-chemical method. The influence of calcination temperature on the phase and morphology of obtained pristine product were characterized using X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). Cyclic voltammogram studies were conducted to examine the electrochemical performance of cathodes made of vanadium oxide nanostructures. X-ray diffraction results show that, the particle size of the nanomaterials is increases with the increasing of calcination temperature.

SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANE BY TETHERING POLYPEPTIDES

Two kinds of polypeptides were tethered onto the surface of polypropylene microporous membrane (PPMM) through a ring opening polymerization of L-glutamate N-carboxyanhydride initiated by amino groups which were introduced by ammonia plasma andγ-aminopropyl triethanoxysilane treatments. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), scanning electron microscopy (SEM), together with water contact angle measurements were used to characterize the modified membranes. XPS analyses and FT-IR/ATR spectra demonstrated that polypeptides are actually grafted onto the membrane surface. The wettability of the membrane surface increases at first and then decreases with the increase in grafting degrees of polypeptide. Platelet adhesion and murine macrophage attachment experiments reveal an enhanced hemocompatibility for the polypeptide modified PPMMs. All these results give evidence that polypeptide grafting can simultaneously improve the hemocompatibility as well as reserve the hydrophobicity for the membrane, which will provide a potential approach to improve the performance of polypropylene hollow fiber microporous membrane used in artificial oxygenator.

Brownian Motion and the Temperament of Living Cells

The migration of living cells usually obeys the laws of Brownian motion.While the latter is due to the thermal motion of the surrounding matter,the locomotion of cells is generally associated with their vitality.We study what drives cell migration and how to model memory effects in the Brownian motion of cells.The concept of temperament is introduced as an effective biophysical parameter driving the motion of living biological entities in analogy with the physical parameter of temperature,which dictates the movement of lifeless physical objects.The locomemory of cells is also studied via the generalized Langevin equation.We explore the possibility of describing cell locomemory via the Brownian self-similarity concept.An heuristic expression for the diffusion coefficient of cells on structured surfaces is derived.

Oxygen vacancies enriched nickel cobalt based nanoflower cathodes: Mechanism and application of the enhanced energy storage

The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.

TiO2-incorporated polyelectrolyte composite membrane with transformable hydrophilicity/hydrophobicity for nanofiltration separation

The wettability of the membrane surface has shown obvious influent on the separation performance of the membrane.In this work,a hydrophilic PDA-[PDDA/TiO2]+Cl-membrane was prepared by a one-step codeposition of poly(diallyldimethylammonium chloride)(PDDA)polyelectrolyte solution containing positively charged TiO2@PDDA nanoparticles with the assistance of dopamine(DA).Such positively charged membrane can be transformed into a hydrophobic membrane PDA-[PDDA/TiO2]+PFO-via the counterion exchange between Cl-and PFO-(perfluorooctanoate).The transformation between hydrophilicity and hydrophobicity is reversible.For both hydrophilic and hydrophobic membranes,the nanofiltration performances were respectively investigated by the aqueous solution and ethanol solution of dyes including methyl blue(MB),Congo red(CR)and Evans blue(EB),and as well metal salt aqueous solution.The consecutive running stability and anti-fouling performance of both hydrophilic and hydrophobic membranes were explored.The results revealed that both membranes showed high nanofiltration performances for retention of dyes in(non)aqueous solution.For the hydrophilic membrane,the rejection of salts in a sequence is MgSO4>Na2SO4>MgCl2>NaCl.Moreover,both of the hydrophilic and hydrophobic membranes showed high stability and antifouling property.

Functional Superoxide Dismutase Mimics Become Diverse: From Simple Compounds on Prebiotic Earth to Nanozymes

Inorganic solids with enzyme-like activity are promising to overcome many restrictions of native enzymes in application.Especially attractive are nanoparticles with superoxide dismutase(SOD)activity,due to their ability to reduce the damaging properties of reactive oxygen species within cells and organism.This review discusses the necessary requirements for nanoparticles to have SOD activity and reveals a close relationship between catalysis on prebiotic earth and the recent SOD mimics.This review also aims to highlight the progress in the development of SOD mimicking nanoparticles.We give a broad overview of nanoparticles with SOD activity,based on their material make-up,to underline their increasing diversity.

Novel Screen-Printed All-Solid-State Copper(II)-Selective Electrode for Mobile Environmental Analysis

Based on poly(vinyl chloride) membranes, a novel miniaturized screen-printed all-solid-state copper(II)-selective electrode has been developed for applications in environmental monitoring. Performance and applicability of the ion-selective electrode (ISE) have been proved by potentiometric investigations. Conducting polymers were used as intermediate layers and as solid contacts between the ion-selective membrane and the graphite transducer. The ion-complexing reagent 2-mercapto-benzoxazole was incorporated into poly(vinyl chloride) membranes. In the concentration range 10-6 - 10-2 mol/L, the ISE exhibited a linear Nernstian potential response to copper(II) with an average slope value of 28 mV/decade. The detection limit was 3 × 10-7 mol/L. The electrode exhibits a short response time (<10 s) and can be used in the range of pH = 3 - 7. Selectivity coefficents against certain interfering ions are investigated. The life time of the electrode under laboratory conditions was approximately 12-month. The electrode was applied in the investigation of different aqueous environmental samples and the electrode characteristics were described. The copper(II) ASS electrode has also successfully been used in potentiometric, complexometric titrations with ethylenediaminetetraacetic acid.

Disposition and Metabolism of 1 -Nitropropane in Rats and Chimpanzees

The metabolic fate of 1 -nitropropane （1-NP） has not been previously reported. In this study male rats and chimpanzees were given single doses of 40 mg/kg ip and 5 mg/kg iv 1-[1-14C]NP, respectively. The quantitative extent of urinary and fecal elimination was similar in both species. The rats excreted 16.5% ofthedosein urine and 1.7% in feces. For chimpanzees the respective values were 14.8 and 1.2%. Experiments with rats demonstrated that the major route of elimination was by exhalation. With a total elimination via the lungs of 72.6%, rats expired 10.3% of the dose as unchanged 1-NP. Five polar metabolites were isolated from the urine of chimpanzees. The two major metabolites were identified as 3-hydroxypropionic acid and 7V-methyl-N-2-（methylsulfinyl）ethylpropionic acid amide （NMPA）. Both substances were also excreted in rat urine. The two identified metabolites indicate that 1-NP was degraded to propionic acid, part of which was modified to 3-hydroxypropionic acid or NMPA. A hypothetical pathway for the biochemical generation of NMPA is suggested.（c）1989 Academic Press, Inc.

Effects of Direction of Bridging of Thiocyanato on the Dimension of Coordination Polymers: Synthesis, Characterization and Single-crystal X-ray Structure Determination of [Cd(4,4'-dm-2,2'-bpy)(NCS)_2]_n and [Cd(4,4'-dmo-2,2'-bpy)(NCS)_2]_n Coordination Pol

Two new cadmium(II)-thiocyanato coordination polymers with 4,4'-dimethyl-2,2'-bipyridine(4,4'-dm-2,2'-bpy) and 4,4'-dimethoxy-2,2'-bipyridine(4,4'-dmo-2,2'-bpy) as chelating ligands were synthesized and characterized by elemental analysis, IR and 1H NMR spectroscopy and X-ray crystallography. Thermal properties were also studied as well. These complexes have formed as [Cd(4,4'-dm-2,2'-bpy)(NCS)2]n(1) and [Cd(4,4'-dmo-2,2'-bpy)(NCS)2]n(2). The coordination numbers of CdII in 1 and 2 are six(Cd N4S2). Direction of bridging of thiocyanato anions in 1 and 2 created one- and two-dimensional coordination polymers, respectively. The supramolecular features in these complexes were guided and controlled by weak directional intermolecular interactions.

Functional Surfactants for Molecular Fishing,Capsule Creation,and Single-Cell Gene Expression

Creating a single surfactant that is open to manipulation,while maintaining its surface activity,robustness,and compatibility,to expand the landscape of surfactant-dependent assays is extremely challenging.We report an oxidation-responsive precursor with thioethers and multiple 1,2-diols for creating a variety of functional surfactants from one parent surfactant.Using these multifunctional surfactants,we stabilize microfluidics-generated aqueous droplets.The droplets encapsulate different components and immerse in a bioinert oil with distinct interfaces where an azide-bearing surfactant allow fishing of biomolecules from the droplets,aldehyde-bearing surfactant allow fabrication of microcapsules,and hydroxyl-bearing surfactants,with/without oxidized thioethers,allow monitoring of single-cell gene expression.Creating multifunctional surfactants poses opportunities for broad applications,including adsorption,bioanalytics,catalysis,formulations,coatings,and programmable subset of emulsions.

Novel Isatin-Schiff Base Cu (II) and Ni(II) Complexes. X-ray Crystal Structure of Bis[3-(4-hexylphenylimino)-1H-indol-2(3H)-one]-dichlorocopper(II) Complex

Schiff base ligand (HL) derived from 4-hexylaniline with isatin (1H-indole-2,3-dione)and its complexes with Cu(II), Ni(II) were prepared and characterized by analytical, spectroscopic(IR, UV-Vis, Mass) techniques, electrical conductivity, magnetic and thermal measurements. Thecrystal and molecular structure of [Cu(HL)2Cl2] was determined by a single-crystal X-raydiffraction study. The molecular structure of the title compound has an inversion center on theCu atom.

Quantum Engineering of Helical Charge Migration in HCCI

Electronic charge of molecules can move on time scales when the nuclei stand practically still,from few hundreds of attoseconds to few femtoseconds.This ultrafast process is called“charge migration”.A typical consequence is rapid change of electronic dipole,which points to the center of charge.Corresponding linear(one-dimensional,1D)and planar(2D)dipolar motions have already been well documented.Here we construct the first case of charge migration which causes chiral 3D dipolar motion,specifically along a helix about oriented iodo-acetylene(HCCI).Quantum dynamics simulations show that this can be induced by well-designed laser pulses.

sp^(3)-like defect structure of hetero graphene-carbon nanotubes for promoting carrier transfer and stability

Three-dimensional(3 D) hybrid of nanocarbons is a very promising way to the high-performance design of electrocatalysis materials.However,sp^(3)-like defect structure,a combination of high strength and conduction of graphene and carbon nanotubes(CNTs) is rarely reported.Herein,3 D neural-like hybrids of graphene(from reduced graphene oxide) and carbon nanotubes(CNTs) have been integrated via sp^(3)-like defect structure by a hydrothermal approach.The sp^(3)-like defect structure endows 3 D nanocarbon hybrids with an enhanced carrier transfer,high structural stability,and electrocatalytic durability.The neural-like structure is shown to demonstrate a cascade effect of charges and significant performances regarding bio-electrocatalysis and lithium-sulfur energy storage.The concept and mechanism of "sp^(3)-like defect structure" are proposed at an atomic/nanoscale to clarify the generation of rational structure as well as the cascade electron transfer.

All-Solid-State Screen-Printed Sensors for Potentiometric Calcium(II) Determinations in Environmental Samples

This paper describes preparation, characterization and electrochemical performance of novel planar miniaturized all-solid-state (ASS) screen-printed potentiometric sensors for the detection of Ca2+ ions in environmental samples. Screen-printed graphite-based ion-selective electrodes (ISEs) and screen-printed reference electrodes based on silver-containing pastes have been applied in a space saving manner on common ceramic substrates with small dimensions. Applications to environmental samples are shown by direct potentiometry and potentiometric titrations in real water samples. Conducting polymers (CPs) have been used as solid-contact materials and as intermediate layer between the polyvinyl chloride (PVC)-containing ion-selective membrane and the graphite-containing substrate. Different diamides have been incorporated into the PVC membrane. In the range from 10-4 mol/L to 10-1 mol/L, the ISEs show linear slopes of 27 mV/decade, which is close to the Nernstian response. Moreover, the ISEs have response times of 6 months. The novel potentiometric ASS sensors enable simple and exact Ca2+ determinations in real samples.

Empirical Review of Standard Benchmark Functions Using Evolutionary Global Optimization

We have employed a recent implementation of genetic algorithms to study a range of standard benchmark functions for global optimization. It turns out that some of them are not very useful as challenging test functions, since they neither allow for a discrimination between different variants of genetic operators nor exhibit a dimensionality scaling resembling that of real-world problems, for example that of global structure optimization of atomic and molecular clusters. The latter properties seem to be simulated better by two other types of benchmark functions. One type is designed to be deceptive, exemplified here by Lunacek’s function. The other type offers additional advantages of markedly increased complexity and of broad tunability in search space characteristics. For the latter type, we use an implementation based on randomly distributed Gaussians. We advocate the use of the latter types of test functions for algorithm development and benchmarking.

苔藓Lophozia ventricosa挥发油化学成分研究(英文)

采用水蒸气蒸馏法提取苔藓Lophozia ventricosa挥发油,用毛细管色谱法对挥发油进行了分析,采用归一化法确定各组分的相对含量,并用GC-MS联用技术对分离的化学成分进行鉴定.经计算机检索并结合文献调研,共鉴定出28个化合物,占挥发油总量的93.3%,其中含1个单萜、23个倍半萜(15个为含氧倍半萜)和1个二萜,主要成分为Maalioxide(45.6%)和Eudesma-4(15),7(11)-dien-8-one(28.9%).

Chemistry-led investigations into the mode of action of NAMPT activators,resulting in the discovery of non-pyridyl class NAMPT activators

The cofactor nicotinamide adenine dinucleotide(NAD+)plays a key role in a wide range of physiological processes and maintaining or enhancing NAD+levels is an established approach to enhancing healthy aging.Recently,several classes of nicotinamide phosphoribosyl transferase(NAMPT)activators have been shown to increase NAD+levels in vitro and in vivo and to demonstrate beneficial effects in animal models.The best validated of these compounds are structurally related to known urea-type NAMPT inhibitors,however the basis for the switch from inhibitory activity to activation is not well understood.Here we report an evaluation of the structure activity relationships of NAMPT activators by designing,synthesising and testing compounds from other NAMPT ligand chemotypes and mimetics of putative phosphoribosylated adducts of known activators.The results of these studies led us to hypothesise that these activators act via a through-water interaction in the NAMPT active site,resulting in the design of the first known urea-class NAMPT activator that does not utilise a pyridine-like warhead,which shows similar or greater activity as a NAMPT activator in biochemical and cellular assays relative to known analogues.

Selected gas response measurements using reduced graphene oxide decorated with nickel nanoparticles

The work reports the synthesis of nickel nanoparticles supported on thermally reduced graphene oxides(rGO)in the ionic liquid[BMIm][NTf_(2)]through microwave decomposition reaction.Ni@rGO with the polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)as binder was positively tested for its response towards the oxidizing gas nitrogen dioxide(10 ppm in air),the reducing gas carbon monoxide(3000 ppm in N_(2))and the volatile organic compound(VOC)acetone(35,000 ppm in air).The results from different gases were compared at different temperatures with the best results for NO_(2) at 200℃.Additionally,it is shown for NO_(2) gas that the Ni@rGO-PEDOT:PSS polymer composite gives better results than the rGO-PEDOT:PSS polymer composite.After the heat treatment the oxidation state of pure nickel nanoparticles were confirmed by powder diffraction.

含长链亚烷基桥的芳炔类共轭大环的合成

采用模板导向法高产率地合成了两个含长链亚烷基桥的芳炔类共轭大环.通过四碘化合物与单保护双炔化合物的四重Hagiraha偶合反应构建了环化所需要的复杂前体.通过相应的模板四炔衍生物的分子内G laser偶合反应环化得到大环.大环的结构用NMR,GPC及UV-V is表征确证.