Surface modified microprojection arrays for the selective extraction of the dengue virus NS1 protein as a marker for disease

While advances in assay chemistry and detection continue to improve molecular diagnostics technology, blood samples are still collected using the 150-year-old needle/syringe method. Surface modified microprojection arrays have been developed as a novel platform for in vivo, needle-free biomarker capture. These devices are gold coated silicon arrays with >20,000 projections per cm(2), which can be applied to the skin for tunable penetration into the epidermis or dermis. The microprojection array conceptually offers several advantages over the current methods including: minimally invasive sample collection, no need for sample processing and concentration of specific markers at the device surface for sensitive detection. In this study, Microprojection arrays were coated with antibodies to capture an early marker of dengue virus infection, NS1, from the skin of live mice. We also developed a complementary "total IgG" assay which could be used as a positive control for adequate penetration of the projections. Surface modifications designed for selective extraction were tested against standard microtiter plate ELISA. We also investigated the use of Protein G-mediated antibody immobilization in order to orient capture antibodies. While we found that capture efficiency could be improved, the direct EDC-based antibody immobilization resulted in a significantly higher surface density leading to a higher degree of NS1 capture. Using mice intravenously injected with recombinant dengue virus type 2 NS1 as a pseudomodel for dengue infection, NS1 was successfully extracted using microprojection arrays sampling from skin fluid, with a detection limit of 8 μg/mL.     

Synthesis and biodistribution of 99m Tc-PyDA as a potential marker for tumor hypoxia imaging

The ^99m Tc-pyrimidine-4,5-diamine (^99m Tc-PyDA) complex was prepared. The yield under the optimum conditions (5 mg of PyDA, pH 8, 25 μg of SnCl₂·2H₂O) was 96 ± 3%. The complex is stable in vitro for 24 h. The complex was tested on mice as potential marker for tumor hypoxia imaging. The complex showed high tumor hypoxia uptake with the target/nontarget (T/NT) ratio as high as ～3.     

KMg2AlSi4O12 phyllosiloxide as potential interphase material for ceramic matrix composites: Part 1 Chemical compatibility

KMg₂AlSi₄O₁₂ is a phyllosiloxide isostructural with phlogopite mica, but totally free of OH^- ions. It decomposes at ≈ 950 °C at atmospheric pressure but remains stable up to at least 1350 °C under high pressures. Its chemical compatibility with α-alumina, MgAl₂O₄ spinel, forsterite, β-SiC and borosilicate glass selected as representative of fibres and matrices in ceramic matrix composites (CMCs), has been assessed via annealing experiments on multilayers and particulate composites at 900–1200 °C. At T = 900 °C and P = 100 MPa, the phyllosiloxide is chemically stable with respect to all the ceramics. At higher temperatures, interdiffusion occurs with the formation of various reaction products. At T = 1050 °C and P = 2 GPa, the extent of the reaction zone is larger for both α-alumina and forsterite than for spinel and β-SiC, whereas at 1200 °C, the reactivity of the phyllosiloxide with all the ceramics becomes about the same. Borosilicate glass with a softening point lower than the decomposition onset of KMg₂AlSi₄O₁₂ at relatively low pressures seems to be an ideal model matrix material for assessing the potential of the phyllosiloxide as an interphase material in CMCs. This revised version was published online in November 2006 with corrections to the Cover Date.     

Characterization of the dealumination effect into H faujasites by adsorption: Part 1. The water molecule as a structural aluminum ion selective probe

The adsorption and desorption isotherms of water vapor are drawn at 25°C for dealuminated HY zeolites upon framework Si/Al ratio. The isotherms are compared to that of the parent NaY zeolite studied in a wide range of temperatures and filling coefficients (0.03 < θ < 1). The isotherm changes in shape from type I to type IV with an hysteresis loop changing from type H4 to type H2, as the Si/Al ratio increases. The Polanyi—Dubinin theory is used to determine the volume accessible to water. It decreases with increasing Si/Al ratios, down to zero at a Si/Al ratio of 35. Such a result is accounted for by the adsorption on the hydrophillic centers, which are the cations (H⁺) associated with the structural aluminum ions, each cation being coordinated on average by 9 H₂O.     

Synthesis and environmental applications of cellulose/ZrO2 nanohybrid as a selective adsorbent for nickel ion

Cellulose/ZrO₂ nanohybrid has been synthesized by simple growth of ZrO₂ on cellulose matrix and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transforms infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Interestingly, FESEM showed nanoparticles with an average size of 50 nm. The analytical potential of the newly prepared nanohybrid was studied for a selective extraction of nickel prior to its determination by inductively coupled plasma-optical emission spectrometry. The selectivity of nanohybrid was investigated toward eight metal ions, including Cd²⁺, Co²⁺, Cr³⁺, Cu²⁺, Fe³⁺, Ni²⁺, Zn²⁺ and Zr⁴⁺. Data obtained from the selectivity study showed that nanohybrid was the most selective toward Ni²⁺. The uptake capacity for Ni²⁺ was experimentally calculated and found to be 79 mg g⁻¹. Moreover, adsorption isotherm data of Ni²⁺ on nanohybrid was well fit with the Langmuir adsorption isotherm, strongly supporting that the adsorption process was mainly monolayer on homogeneous adsorbent surfaces. Finally, data of Ni²⁺ adsorption on nanohybrid as a function of contact time displayed that equilibrium kinetics are very fast.     

Synthesis of MoX2 (X = Se or S) monolayers with high-concentration 1T′ phase on 4H/fcc-Au nanorods for hydrogen evolution

Controlled synthesis of transition metal dichalcogenide (TMD) monolayers with unusual crystal phases has attracted increasing attention due to their promising applications in electrocatalysis. However, the facile and large-scale preparation of TMD monolayers with high-concentration unusual crystal phase still remains a challenge. Herein, we report the synthesis of MoX₂ (X = Se or S) monolayers with high-concentration semimetallic 1T′ phase by using the 4H/face-centered cubic (fcc)-Au nanorod as template to form the 4H/fcc-Au@MoX₂ nanocomposite. The concentrations of 1T′ phase in the prepared MoSe₂ and MoS₂ monolayers are up to 86% and 81%, respectively. As a proof-of-concept application, the obtained Au@MoS₂ nanocomposite is used for the electrocatalytic hydrogen evolution reaction (HER) in acid medium, exhibiting excellent performance with a low overpotential of 178 mV at the current density of 10 mA/cm², a small Tafel slope of 43.3 mV/dec, and excellent HER stability. This work paves a way for direct synthesis of TMD monolayers with high-concentration of unusual crystal phase for the electrocatalytic application.

     

Characterization of carbon nanotubes decorated with NiFe2O4 magnetic nanoparticles as a novel electrochemical sensor: Application for highly selective determination of sotalol using voltammetry

A magnetic nano‐composite of multiwall carbon nanotube, decorated with NiFe₂O₄ nanoparticles, was synthesized with citrate sol–gel method. The multiwall carbon nanotubes decorated with NiFe₂O₄ nanoparticles (NiFe₂O₄–MWCNTs) were characterized with different methods such as Fourier transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), atomic force microscopy (AFM), vibrating sample magnetometer (VSM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The new nano-composite acts as a suitable electrocatalyst for the oxidation of sotalol at a potential of 500 mV at the surface of the modified electrode. Linear sweep voltammetry exhibited two wide linear dynamic ranges of 0.5–1000 μmol L^? 1 sotalol with a detection limit of 0.09 μmol L^? 1. The modified electrode was used as a novel electrochemical sensor for the determination of sotalol in real samples such as pharmaceutical, patient and safe human urine.     

Phase-pure Na3V2(PO4)2F3 embedded in carbon matrix through a facile polyol synthesis as a potential cathode for high performance sodium-ion batteries

In this study, a pseudo-layered Na super-ionic conductor of Na₃V₂(PO₄)₂F₃ (NVPF)/C cathode for sodium-ion batteries is prepared successfully using a facile polyol refluxing process without any impurity phases. The X-ray diffraction and Rietveld refinement results confirm that NVPF possesses tetragonal NASICON-type lattice with a space group of P₄₂/mnm. In this preparative method, polyol is utilized as a solvent as well as a carbon source. The presence of nanosized NVPF particles in the carbon network is confirmed by field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM). The existence of carbon is analyzed by Raman scattering and elemental analysis. When applied as a Na-storage material in a potential window of 2.0–4.3 V, the electrode exhibits two flat voltage plateaus at 3.7 and 4.2 V with an electrochemically active V³⁺/V⁴⁺ redox couple. In addition, Na₃V₂(PO₄)₂F₃/C composite achieved a retention capacity of ~ 88% even after 1,500 cycles at 15 C. Moreover, at high current densities of 30 and 50 C, Na₃V₂(PO₄)₂F₃/C cathode retains the specific discharge capacities of 108.4 and 105.9 mAh·g^–1, respectively, revealing the structural stability of the material prepared through a facile polyol refluxing method.

     

Concentration dependence ofD,T 1, andT 2 for dilute solutions of3He in solid4He

Measurements of the spin diffusion coefficientD and NMR relaxation timesT ₁ andT ₂ are reported for dilute solutions of³He in solid⁴He at two molar volumes, 20.95 and 20.7 cm³. The weakly interacting impuriton model, for whichD ^–1 is proportional to impurity concentration, is observed only at fractional impurity concentrationx ₃ below 3 × 10^–4. Forx ₃ around 10^–3,T ₁ andT ₂ are controlled by the formation and breakup of³He₂ molecules.     

T c as a Function of Electron Doping in Mg10B2 Using Sc for Mg Substitution

We have studied the variation of superconducting critical temperature T _c as a function of electron doping in the Mg¹⁰B₂ system using Sc for Mg substitution. The critical temperature in the¹⁰B isotope substituted system Mg_{1? x} Sc _x ¹⁰B₂ increases by increasing the scandium content x in the range 0<x<0.012 up to 41.4 K, while the T _c of the natural boron system Mg_{1? x} Sc _x B₂ is nearly constant. The overall difference of T _c in Mg_{1? x} Sc _x B₂ as function of x between the natural B and ¹⁰B isotope system seems to indicate that the isotope effect shows large variations with electron doping as expected for the T _c enhancement driven by a shape resonance.     

ZnCo2O4 nanorods as a novel class of high-performance adsorbent for removal of methyl blue

Spinel ZnCo₂O₄ nanorods were synthesized by a simple template-free hydrothermal method in the presence of zinc chloride, cobalt chloride, glucose, and urea. The phase structure, morphology and chemical composition have been characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED). The results showed that the typically porous and poly-crystalline structure was successfully grown on the surface of ZnCo₂O₄ nanorods. The ZnCo₂O₄ nanorods were further applied to remove methyl blue (MB), which was used as a model of organic pollutants in aqueous solution. In particular, the maximum equilibrium adsorption capacity of MB in ZnCo₂O₄ nanorods reaches up to 2400?mg/g, which is higher than that of most adsorbents. The adsorption isotherms and kinetics followed standard Langmuir and pseudo-second-order models, respectively. MB adsorption decreased with increasing solution pH at pH?>?7 implying that MB adsorption on ZnCo₂O₄ nanorods may via chemisorption between negatively charged MB molecular and positively charged adsorption sites on the surface of ZnCo₂O₄ nanorods. This study provides great promise of using ZnCo₂O₄ nanorods as adsorbent for removal of pollutant dyes.     

新型超级电容器电极材料NaxCo2O4的制备及电性能研究

采用溶胶-凝胶法制备得到Na x Co2O4(x=1.0、1.2、1.4、1.6、1.8和2.0)样品,并首次将其应用于超级电容器电极材料;经XRD、SEM和电性能研究得出,制备出的Na x Co2O4晶体均为层状结构,x=1.6时样品电容性能最好,在6mol/L NaOH电解液中,0.25~0.7V电压范围内,以50mA/g的电流密度进行恒流充放电,比电容高达413F/g。     

Design and simulation of a heat pump for simultaneous heating and cooling using HFC or CO2 as a working fluid

This article presents a Heat Pump for Simultaneous heating and cooling (HPS) designed for hotels, luxury dwellings and smaller office buildings. The main advantage of the HPS is to carry out simultaneously space heating and space cooling in a dual mode. The ambient air is used as a balancing source to run a heating or a cooling mode. The HPS also participates to domestic hot water preparation all year round. The second advantage is that, during winter, some energy recovered by subcooling of the refrigerant is stored at first in a cold water tank that is not used for cooling. This energy is used subsequently as a cold source at the water evaporator in order to improve the average coefficient of performance and to run a defrosting sequence at the air evaporator. Two refrigerants are studied: HFC R407C and carbon dioxide. HFCs provide good performance, but new restrictive regulations on F-gases lead us to study low-GWP refrigerants as well. Highly efficient models of compressors and heat exchangers have been defined. Annual simulations show that CO₂ is a refrigerant which adapts rather well to the operation of the HPS thanks to the higher amount of energy available by subcooling and the large temperature glide at heat rejection used for DHW production.     

锂离子电池阴极材料Li_(1+x)Mn_2O_4的合成与特性

对Ｌｉ１＋ｘＭｎ２Ｏ４的合成性能进行了初步的探索。原材料采用分析纯Ｌｉ２ＣＯ３和电解二氧化锰，对原材料ＭｎＯ２进行热处理，使之成为ε相并排除结晶水。制备了四个系列的样品，其各自的ｘ含量、首次加热温度、再次加热温度、退火方式有所不同。对样品进行ＸＲＤ分析及电性能测试，说明了ＭｎＯ２中必须除去结晶水的原因，找到了最佳合成温度范围，确定了最佳性能时的ｘ值。     

Surface and interface engineering of Z-scheme 1D/2D imprinted CoZn-LDH/C3N4 nanorods for boosting selective visible-light photocatalytic activity

Recently, the emergence of more and more coexisting organic contaminants aggravates the difficulty of water treatment and poses a threat to public health. Molecularly imprinted photocatalysts allow a highly selective removal of target active compounds, rendering wide applications in complex environmental treatment. However, the synergistic recognition and degradation performance is usually restricted by the intrinsic structural characteristics of traditional photocatalysts and the affinity barrier between semiconductor substrate and organic imprinted layer. Herein, we synthesized Z-scheme molecularly imprinted photocatalysts with CoZn-LDH heterostructure supported by porous C₃N₄ nanorods (MIP-CoZn-LDH@C₃N₄). Due to the excellent light capture and high active cavities, the photodegradation rate of MIP-CoZn-LDH@C₃N₄ to tetracycline (TC) target could reach 79.8% under visible light within 60 min. Noticeably, the material possessed outstanding ability of selective recognition and photodegradation of TC in coexisting interference solution (k_imprinted was 2.18 to ciprofloxacin and 2.33 to cephalothin, respectively). The mode of selective photodegradation and pathways were systematically discussed based on the deep evaluation of the mechanism experiments. Our study opens a new insight into the design of photocatalyst with selective degradation performance for the requirements of practical environmental applications.     

Cd(2+) Complex of a Triazole-Based Calix[4]arene Conjugate as a Selective Fluorescent Chemosensor for Cys

An N,N-Dimethylamine ethylimino-appended triazole-linked calix[4]arene conjugate, L, has been synthesized and characterized, and its Cd(2+) complex has been isolated and characterized. The structure of [CdL] was established by computational calculation using B3LYP/LANL2DZ. Time-dependent density functional theory calculations were performed to demonstrate the electronic properties of [CdL]. This highly fluorescing [CdL] has been used to recognize Cys selectively among the 20 naturally occurring amino acids. [CdL] exhibits a minimum detection limit of 58 ppb for Cys, with reusability and reversibility being imparted to the system during sensing. Thus, the sensing of Cys was well demonstrated using various techniques, viz., fluorescence, absorption, visual color change, electrospray ionization MS, (1)H NMR, and live cell imaging experiments.     

On the changes in a structure of water due its contact with a solid phase. III. Determination of relations T1/T1 0=f1(m/M), Me=f2(α). Estimation of variation effect of the valence angle (α) in a water molecule on water solubility of substances

Calculated and experimental methods have been suggested to determine the valence angle in a water molecule in a volume with the solid phase mass variation in a system. The dependences of the dipole moment in H₂O and of static dielectric water permeability on the valence angle value have been established and the changes in water solubility of different substances in the presence of a solid phase have been substantiated.Central Research Institute for Complex Utilization of Water Resources, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 63, No. 1, pp. 80–87, July, 1992.