Electrochemical formation and phase control of Mg-Li alloys

The electrochemical formation of Mg-Li alloys was investigated in a molten LiCl-KCl(58-42 mol%)eutectic melt at 723 K. The cyclic voltammogram for a Mo electrode showed that the electroreduction of Li~ proceeds in a single step and the deposition potential of Li metal was -2.40 V(vs.Ag/AgCl).For Mg electrode,the electroreduction of Li~ takes place at less cathodic potential than that at the Mo electrode which was caused by the formation of Mg-Li alloys.Phase of the deposited Mg-Li alloys could be controlled by the electrolysis potential,and the samples were characterized by X-ray diffraction and scanning electron microscopy. The results showed thatα-Mg andβ-Li phases were obtained at -2.35 and -2.55 V,respectively.     

Screening the anti-gout traditional herbs from TCM using an in vitro method

The aim of this work was to evaluate the ability of 33 herbal extracts in inhibiting the acute inflammation and xanthine oxidase(XOD) activity.The anti-inflammation effects of the herbal extracts were detected by an in vitro cell model,which was established by stimulating human umbilical vein endothelial cells(HUVEC) using sodium urate(MSU).In this model,the intercellular adhesion molecule-1(ICAM-1) and interleukin-1 beta(IL-1β) were expressed,and the anti-inflammation effects of herbal extracts were evaluated by detecting the content changes of ICAM-1 and IL-1β in cell lysates and cell culture supernates using an enzyme-linked immunosorbent assay(ELISA).Moreover,an ultrahigh performance liquid chromatography and tandem mass spectrometry(UPLC-MS/MS) method was used for the detection of XOD activity and the screening of XOD inhibitors in this research.The amount of uric acid from each analyte was directly detected using the multiple reaction monitoring mode and the uric acid level could be reduced via the addition of an inhibitor.Results indicated that Salviae Miltiorrhizae Radix et Rhizome,Rhei Radix et Rhizoma,Polygoni Cuspidati Rhizoma et Radix,Selaginellae Herba,Paeoniae Radix Rubra,especially Ginkgo Folium seemed to be more effective in anti-inflammation and inhibiting XOD activity.The anti-inflammation and enzyme inhibitory activities of the herbal extracts may be correlated with their bioactive components.And the differences between the herbal extracts were correlated with the amount of flavonoid and anthraquinone components.In our study,we have investigated the potential anti-inflammation bioactivity of 33 herbal extracts in vitro,which could provide a reference for further in vivo research in the prevention and treatment of gout.     

Depression of Calcium Transients After Exposure to High K~+ Solution in Li~+-loaded Frog Twitch Muscle Fibres and Its Reversal by Exogenous Myo-inositol

Using Arsenazo Ⅲ as a myoplasmic calcium indicator, we have studied the calcium transients evoked by voltage-clamp depolarizing pulses in frog twitch muscle fibres which had been temporarily depolarized by 80 mmol/LK~+ in the absence or presence of myoplasmic Li~+. After the high K~+ exposure, for either a short (15 rain) or long(1 h) time, the post-K~+ calcium transients could gradually be restored to the level of the pre-K~+ ones, if the fibres were not loaded with Li~+.In contrast, the post-K~+ calcium transients of Li~+-loaded fibres could not fully recover,and were depressed in a Li~+ concentration-dependent manner.The mean amplitude of the post-K~+ responses recorded more than 3.5 h after 15 min high K~+ exposure was reduced to 56% of pre-K~+ control in the fibres which had been loaded with Li~+ in 20 mmol/L Li~+ Ringer's solution.This depression could be prevented or partially reversed by exogenous myo-inositol.More depression could be induced by 1 h high K~+ exposure, but the presence of exogen     

PVP为模板控制合成球形碳酸钙

Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride at the presence of a protein-like molecule， polyvinylpyrrolidone， as the template. The products were characterized by elemental analyses， XRD， SEM， and TG-DSC respectively. The effects of polyvinylpyrrolidone on the crystal form and morphology of the as-prepared CaCO₃ were investigated. It was found that the aggregative shape of the produced calcium carbonate crystalline could be well controlled by adjusting the concentration of the polyvinylpyrrolidone template. This may be of important meanings to the biomimetic synthesis of novel inorganic materials.     

Removal of residual nitrate ion from bioactive calcium silicate through soaking

Bioactive calcium silicates prepared by sol–gel routes mainly use calcium nitrate as the calcium precursor. However, the toxic nitrate ions are usually removed by calcination(i.e. 550 8C or over), which poses great challenge for the in situ preparation of inorganic/polymer composites, as polymer moieties could not survive such temperatures. In this study, we prepared 70Si30Ca(70 mol% Si O_2 and 30 mol%Ca O) bioactive glass at low temperatures where polymer could survive(i.e. 200 8C and 350 8C), and proposed to remove the residual nitrate ions through soaking. Deionized water and simulated body fluid(SBF) were employed as the soaking medium. The results showed that the residual nitrate ions could be removed as quickly as 0.5 h while maintain the bioactivity of the samples. This technique may open the possibility of preparing sol–gel derived bioactive glass/polymer hybrids in situ with reduced potential toxicity.     

A novel real-time cell electronic analysis technology for the authentication and quality control of natural medicines

The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles （TCRPs） were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia （edition 2010） was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples ofFlos Carthami can produce remarkably similar TCRPs. The quality ofFlos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aim of our study is to establish a new standard for quality evaluation.     

生物相容性BAB型两亲嵌段共聚物的合成及其自组装

Lys(z)-NCA was synthesized in the presence of triphosgene, amphiphilic triblock copolymers poly(N^c-CBZ-Lysine)-PEG-poly(N^c-CBZ-Lysine) were synthesized in DMF using amino-end ended PEG as initiator with the mechanism of anion ring opening polymerization. The structures of block copolymers were characterized by IR, ^1H-NMR,GPC and DSC. The results showed triblock copolymers with expected structure and low polydispersity in molecular weight could be synthesized by this method. At the same time, the self-assembling behaviors of block copolymer were investigated by TEM. A novel helical aggregates were found to be formed in DMF. Because of biocompatibility of two components of block copolymers, these block copolymers have potential applications in the field of biomaterials.     

Time-resolved monitoring of heavy-metal intoxication in single hair by laser ablation ICP–DRCMS

The potential of laser ablation inductively coupled plasma mass spectrometry for the time-resolved analysis of heavy-metal intoxication in human bodies by analysis of hair is demonstrated. As application, we analyzed forensic samples from one individual after Hg intake and from one treated with a Pt-containing cytostatic remedy. Single hairs were analyzed from the hair root to the tip by laser ablation ICP–MS with a spatial resolution of 20 μm (corresponding to approx. 2 h growth of the hair). Sulfur was used as internal standard and was analyzed by using oxygen as reaction gas in the dynamic reaction cell of the ICP–DRCMS. The detection limits for Hg and Pt were found to be 0.3 μg g^–1 and 0.5 ng g⁻¹, respectively. Standard uncertainties for the quantification results were 10% for Hg and approximately 15 % for Pt. The analyzed hair samples reflected the forensic evidence in both cases. A significant increase of Hg concentration, by a factor of 50, at the time of HgO administration could be shown, and variation of Pt in the hair strands could be used to monitor the time and relative amount of Pt intake by the patient. The investigations also revealed that the concentrations in the outer and the inner parts of the hair varied similarly with time, even though the concentration in the core of the hair is approximately 0.25 that at the surface for both Pt and Hg.     

Influence of lanthanum stearate and calcium/zinc stabilizers on stabilization efficiency of dibutyltin dilaurate to polyvinyl chloride

<正>Influences of lanthanum stearate(LaSt_3) and calcium stearate/zinc stearate(Ca/Zn) stabilizers on stabilization efficiency of dibutyltin dilaurate(DBTDL) to polyvinyl chloride(PVC) in air were investigated.The results revealed that the stabilization effect of DBTDL could be achieved by the La/Sn stabilizers with a ratio of 8/2.Addition of DBTDL could enhance thermal property and reduce dynamic storage modulus(G′) at 180℃for PVC containing LaSt_3 or Ca/Zn stabilizers. On the other hand,incorporation of LaSt_3 did not influence the stabilization efficiency of DBTDL markedly;while addition of Ca/Zn stabilizers could significantly decrease thermal property for the DBTDL stabilized PVC.Furthermore,the effects of LaSt_3 and Ca/Zn stabilizers on the stabilization efficiency of DBTDL were explained in the framework of ionization potential.     

The synthesis and cytotoxic activity of novel organogermanium sesquioxides with anthraquinone or naphthalene moiety

Four novel organogermanium sesquioxides with anthraquinone or naphthalene moiety were synthesized.The structures were characterized by IR,NMR and elemental analysis,and their cytotoxicities were evaluated against human chronic myeloid leukemia K562 cell lines.The cytotoxicity could be improved by the introduction of planar aromatic chromophore moiety to the parent compound,Ge-132.     

An on-line galvanic cell-generated electrochemiluminescence and flow injection determination of calcium in milk and vegetables.

An on-line Ag/Al galvanic cell was studied and employed to generate electrochemiluminescence (ECL) of calcein blue. The potential of the galvanic cell could be adjusted by varying the components of flow reagent or by using different metals to substitute for Ag or Al. The reported cell exhibited perfect capability of supplying a stable potential for ECL generation. Because the weak ECL of calcein blue could be greatly sensitized in the presence of calcium in alkaline solution, calcium contents in milk and vegetable samples were assayed; the results were validated with ICP-AES method. The method gave linear results in 1.0 x 10(-4) mol L(-1) to 8.0 x 10(-6) mol L(-1) calcium concentration range and the 3(sigma)limit of detection was to be 2.0 x 10(-6) mol L(-1). Experiment results imply that this model of ECL detection could be applied for instrument miniaturization with easy fabrication.     

Sensors based on galvanic cell generated electrochemiluminescence and its application

In this paper, a novel electrochemiluminescence (ECL) imaging sensor array was developed for determination of hydrogen peroxide (H₂O₂), which was based on Cu/Zn alloy galvanic cell generated ECL. In alkaline solution, Cu/Zn galvanic cell was formed because of corrosion effect, the galvanic cell could supply stable potential for ECL generation of luminol, and the weak ECL emission could be enhanced by H₂O₂. The galvanic cell sensor array was designed by putting Cu/Zn alloy in 96-well microtiter plates separately. The relative ECL intensity was proportional with the concentration of hydrogen peroxide in the range of 1.0 × 10⁻⁶ to 1.0 × 10⁻⁴ mol l⁻¹ and the detection limit was 3.0 × 10⁻⁷ mol l⁻¹ (3σ), the relative standard deviation (R.S.D.) for 11 parallel measurements of 1.0 × 10⁻⁵ mol l⁻¹ H₂O₂ was 4.0%.     

在线自发电源激发的流动注射电致化学发光测定异烟肼

采用了一种与流动注射体系组合的在线自发电池作为电致化学发光的激发源（ 简称FI－GCECL）。实验发现在碱性介质中，Al/Ag双金属对可以提供稳定的电位输 出并可激发鲁米诺在铂电极表面的电致化学发光。此自发电池具有使用寿命长、电 位可由碱性介质组成调节、可组合到流动注射体系中等特点，利用这种组合体系， 检测了三家厂生产的片剂中的异烟肼含量，将结果与药典标准方法进行了比较，证 明了这种电致发光分析的可行性。     

Dual Intramolecular Electron Transfer for In Situ Coreactant‐Embedded Electrochemiluminescence Microimaging of Membrane Protein

The demand for transporting coreactant to emitter and short lifetime of the radicals in electrochemiluminescence (ECL) emission inhibit greatly its application in cytosensing and microscopic imaging. Herein we designed a dual intramolecular electron transfer strategy and tertiary amine conjugated polymer dots (TEA‐Pdots) to develop a coreactant‐embedded ECL mechanism and microimaging system. The TEA‐Pdots could produce ECL emission at +1.2 V without need of coreactant in test solution. The superstructure and intramolecular electron transfer led to unprecedented ECL strength, which was 132 and 45 times stronger than those from the mixture of Pdots with TEA at equivalent and 62.5 times higher amounts, respectively. The ECL efficiency was even higher than that of typical [Ru(bpy)₃]²⁺ system. Therefore, this strategy and coreactant‐embedded ECL system could be used for in situ ECL microimaging of membrane protein on single living cells without additional permeable treatment for transporting coreactant. The feasibility and validity were demonstrated by evaluating the specific protein expression on cell surface. This work opens new avenues for ECL applications in single cell analysis and dynamic study of biological events.     

Determination of nitrite based on its quenching effect on anodic electrochemiluminescence of CdSe quantum dots

A novel method for electrochemiluminescent (ECL) detection of nitrite was proposed based on its quenching effect on anodic ECL emission of CdSe quantum dots (QDs). The ECL emission could be greatly enhanced by sulfite and dissolved oxygen in a neutral system and occurred at a relatively low potential in comparison with traditional anodic ECL emitter, leading to high sensitivity and good selectivity. The quenching mechanism followed an “electrochemical oxidation inhibition” process, which was completely different from those of some analytes on the ECL emission of QDs. The coincidence of photoluminescence and ECL spectra of the QDs indicated that the ECL emission resulted from the redox process of QDs core and the sulfite acted as a coreactant. The nitrite quenched ECL emission could be analyzed according to the treatment of Stern-Volmer equation with a linear range from 1 μM to 0.5 mM for detection of nitrite. This work presented a new efficient ECL methodology for quencher-related detection.     

鲁米诺在铂热控微电极上的电致化学发光行为研究

研究了鲁米诺在铂热控微电极上的电致化学发光(ECL)行为。当电极表面温度为25℃时,在0.80 V有一个明显的ECL峰(ECL-2);当电极表面温度高于43℃时,鲁米诺在0.45 V和0.80 V各出现一个ECL峰(ECL-1和ECL-2),而且这两个峰的强度随着电极表面温度的变化而变化。同时,对各ECL信号的发光机理进行了探讨。     

Electrochemical and Electrochemiluminescence Determination of Cancer Cells Based on Aptamers and Magnetic Beads

The electrochemical and electrochemiluminescence (ECL) detection of cell lines of Burkitt’s lymphoma (Ramos) by using magnetic beads as the separation tool and high‐affinity DNA aptamers for signal recognition is reported. Au nanoparticles (NPs) bifunctionalized with aptamers and CdS NPs were used for electrochemical signal amplification. The anodic stripping voltammetry technology employed for the analysis of cadmium ions dissolved from CdS NPs on the aggregates provided a means to quantify the amount of the target cells. This electrochemical method could respond down to 67 cancer cells per mL with a linear calibration range from 1.0×10² to 1.0×10⁵ cells mL^?1, which shows very high sensitivity. In addition, the assay was able to differentiate between target and control cells based on the aptamer used in the assay, indicating the wide applicability of the assay for diseased cell detection. ECL detection was also performed by functionalizing the signal DNA, which was complementary to the aptamer of the Ramos cells, with tris(2,2‐bipyridyl) ruthenium. The ECL intensity of the signal DNA, replaced by the target cells from the ECL probes, directly reflected the quantity of the amount of the cells. With the use of the developed ECL probe, a limit of detection as low as 89 Ramos cells per mL could be achieved. The proposed methods based on electrochemical and ECL should have wide applications in the diagnosis of cancers due to their high sensitivity, simplicity, and low cost.     

Efficient electrogenerated chemiluminescence from cyclometalated iridium(III) complexes

Very efficient electrogenerated chemiluminescence (ECL) phenomena were realized by deliberately tuning electron-transfer reactions from electrochemically generated electron donor to metal complex radical cations. By controlling the relative positions of HOMO and LUMO levels (oxidation potential and reduction potential) of Ir(III) complexes, we could obtain 77 times higher ECL from iridium(III) complexes in the presence of TPA than that of the Ru(bpy)32+/TPA system. This high ECL efficiency of new Ir(III) complexes can be used in many interesting applications such as sensors and luminescent devices.     

A sensitive, non-damaging electrochemiluminescent aptasensor via a low potential approach at DNA-modified gold electrodes

Electrochemiluminescence (ECL)-based biosensors are often used in the field of DNA- and protein-assay. Although ruthenium complex-based ECL is sensitive, its high exciting potential may lead to oxidation damage to biomolecules. For the first time, a non-damaging, low potential ECL aptasensor was constructed for bioassay with lysozyme as a model. After a single-stranded anti-lysozyme aptamer was attached to a gold electrode, a double stranded (ds)-DNA formed with its complementary strand. Ru(phen)(3)(2+), as an ECL probe, was intercalated into the ds-DNA. The hybridization of lysozyme with its aptamer led to the dissociation of ds-DNA because of the high stability of the aptamer-lysozyme and therefore the Ru(phen)(3)(2+) intercalated into ds-DNA was released. A low potential ECL was observed at the ds-DNA-modified electrode because ds-DNA was able to preconcentrate tripropylamine (TPA) and acted as the acceptor of the protons released from protonated TPAH(+). While the DNA sequence (anti-lysozyme aptamer) was used as the special recognition element for lysozyme, the formed ds-DNA also provided a micro-environment for low potential ECL. The low potential ECL aptasensor achieved the determination of lysozyme with a detection limit of 0.45 pM. The day-to-day precision (RSDs, n = 5) for the determination of lysozyme was lower than 5%, showing the reliability of the aptasensor. The regeneration of the aptasensor confirmed that the low potential for ECL could decrease oxidation damage to biomolecules. Further, the proposed method was successfully used to analyze diluted egg white sample directly. The protocol exhibited a promising platform for sensitive bioassay and could be further applied for the development of other low potential ECL sensing systems.     

Highly efficient quenching of coreactant electrogenerated chemiluminescence by phenolic compounds

We describe the quenching effects of phenolic compounds on the electrogenerated chemiluminescence (ECL) of the Ru(bpy)3(2+) (bpy = 2,2'-bipyridine)/tri-n-propylamine (TPrA) system in aqueous solution. First, the emissions via different ECL routes were examined in the presence of 1,4-benzoquinone. It was found that the interception of the ECL intermediate radicals by the quencher molecules significantly influenced the light emission, especially when the direct coreactant oxidation played a predominant role in producing ECL. The most efficient quenching was observed for the low-oxidation-potential (LOP) ECL at a low concentration of TPrA (<5 mM). The Stern-Volmer constant (K(SV)) of the LOP ECL quenching could be as high as 1.3 x 10(6) M(-1), approximately 700 times larger than that of the photoluminescence quenching. Other phenolic compounds, such as phenol, hydroquinone, catechol, and dopamine, would be oxidized at the potential where the ECL was generated, and the benzoquinone-containing products exhibited ECL quenching effects similar to that of 1,4-benzoquinone. The highly efficient quenching of the LOP ECL by the phenolic compounds may provide a new approach for the determination of these pharmaceutically and environmentally important molecules.