New composite films based on MoO<Subscript>3−<Emphasis Type="Italic">x</Emphasis></Subscript> nanowires aligned in a liquid single crystal elastomer matrix

Abstract  

In this study, we report the preparation, structure characterization, and application of new MoO_3−x nanowires, promising candidates for lithium intercalation, hydrogen sensing, and smart windows due to their photochromic property. These nanowires are a mixture of MoO₃ and conductive Mo₅O₁₄ phase and have been used to prepare composite films based on liquid single crystal elastomers (LSCE). The structure, morphology, and thermomechanic behavior of these films are discussed. In particular, we show that the particular combination of molybdenum-based nanowires and LSCEs allows for doping of liquid single crystal elastomers, preserving the pristine mechanical and optical properties of the host matrix.     

Electrochemical EDTA recycling after soil washing of Pb, Zn and Cd contaminated soil

Recycling of chelant decreases the cost of EDTA-based soil washing. Current methods, however, are not effective when the spent soil washing solution contains more than one contaminating metal. In this study, we applied electrochemical treatment of the washing solution obtained after EDTA extraction of Pb, Zn and Cd contaminated soil. A sacrificial Al anode and stainless steel cathode in a conventional electrolytic cell at pH 10 efficiently removed Pb from the solution. The method efficiency, specific electricity and Al consumption were significantly higher for solutions with a higher initial metal concentration. Partial replacement of NaCl with KNO₃ as an electrolyte (aggressive Cl⁻ are required to prevent passivisation of the Al anode) prevented EDTA degradation during the electrolysis. The addition of FeCl₃ to the acidified washing solution prior to electrolysis improved Zn removal. Using the novel method 98, 73 and 66% of Pb, Zn and Cd, respectively, were removed, while 88% of EDTA was preserved in the treated washing solution. The recycled EDTA retained 86, 84 and 85% of Pb, Zn and Cd extraction potential from contaminated soil, respectively.     

New molecular and field evidences for the implication of mycotoxins but not aristolochic acid in human nephropathy and urinary tract tumor

To find out whether ochratoxin A (OTA), citrinin (CIT), aristolochic acids (AA) are etiologic agents of Balkan endemic nephropathy (BEN) or Chinese herbal nephrotoxicity, and associated urinary tract tumor (UTT), we have compared (i) in human kidney cell culture, the DNA adduct formation and persistence of OTA/CIT and AA adducts (ii) analyzed DNA adduct in several tumors from human kidney suspected to be exposed to either OTA and CIT, or AAs (iii) analyzed OTA, CIT, and AA in food. In kidney cell cultures, formation of specific OTA-DNA adduct and AA-DNA adduct were detected in the same range (around 10 adducts/10(9) nucleotides) and were time- and dose-dependent. After 2 days all disappeared. DNA adduct related to OTA and CIT are found in human kidney tissues from Balkans, France, and Belgium whereas no DNA adducts related to AA could be found in any tumors of BEN patients from Croatia, Bulgaria, or Serbia. No DNA adduct was found in kidney biopsy or necropsy of the French women suspected to be exposed to AA. OTA and CIT are more frequently found in rural area. AA was never detected. All these plead for implication of mycotoxins, especially OTA, in BEN and UTT.     

Comparative study of primary and secondary metabolites in apricot (Prunus armeniaca L.) cultivars

BACKGROUND: Apricot is one of the most popular Prunus species grown in the temperate zone and great variation in the contents of primary and secondary metabolites has been reported in its fruit. However, little is known on the phenolic profiles and antioxidant potential of important local cultivars. The objective of the study was to identify valuable parental lines for breeding of cultivars with high health‐promoting effects. RESULTS: Primary metabolites (sugars, organic acids) and secondary metabolites (phenolics) were quantified by high‐performance liquid chromatography–mass spectrometry (HPLC/MS) in fruit of 13 apricot cultivars: total sugars ranged from 59.2 to 212.5 g kg^?1 fresh weight (FW) and total organic acids from 4.2 to 20.8 g kg^?1 FW. Four hydroxycinnamic acids and three flavonols were quantified; their content was significantly higher in skin compared to pulp. Similarly, antioxidative potential was significantly higher in skin and ranged from 125.4 to 726.5 mg ascorbic acid equivalents kg^?1 FW. A positive correlation between total phenolic content and antioxidant potential was determined. Multivariate analysis subdivided the cultivars into five major groups, mostly influenced by the content of individual and total phenolics as well as the antioxidant potential of apricot skin and pulp. CONCLUSION: In regard to high phenolic content in connection with antioxidant potential, three cultivars stand out as the richest in analyzed quality parameters: ‘Mula Sadik’, ‘Bergeron’ and ‘Chuan Zhi Hong’. They also contained high amounts of primary metabolites and should be promoted for further planting and included in apricot breeding programs. Copyright © 2010 Society of Chemical Industry     

Noise analysis of the UHF RFID system

Noise is one of the most important parameters in designing a radio frequency (RF) system. Especially in ultra-high frequency (UHF) RF identification (RFID) systems noise plays and important role. This is because the noise performance of the receiver chain is defined not only by the intrinsic noise of the receiver, but also by the large self-jammer signal. This self-jammer signal on the one hand requires that the receiver is designed for high input dynamic range which increases the intrinsic noise of the receiver. On the other hand this self-jammer signal through the effects of reciprocal mixing and range correlation contributes significantly to the total noise of the receiver. To our knowledge this is the first work that deals in detail with the amplitude and phase noise in a UHF RFID system.     

Ce对Al-Si-Cu合金中α(Al)-Al_2Cu共晶形貌的影响(英文)

采用热分析、光学显微镜技术、扫描电镜技术、聚焦离子束和能量色散谱分析方法研究Ce对Al-Si-Cu合金中α(Al)-Al2Cu共晶形貌的影响。结果表明,在枝晶、硅和AlSiFeMn之间较小空间内形成了α(Al)-Al2Cu共晶。Al2Cu为非层状的不规则共晶组织。Al2Cu在经Ce改性的合金中更加致密。部分Ce溶解于Al2Cu中,这是粗晶Al2Cu形成的原因。与基体Al-Si-Cu合金相比,Ce的加入能使α(Al)-Al2Cu共晶合金的显微硬度提高约10%。     

Evaluation of Optimal Conditions for Determination of Low Tin Content in Fresh and Canned Tomato Samples Using Hydride Generation Inductively Coupled Plasma Optical Emission Spectrometry

We propose a procedure for the determination of tin in tomatoes after wet digestion of the samples in HNO₃ using hydride generation inductively coupled plasma optical emission spectrometry. The effect of acidity from HCl and HNO₃ (0.01–4.0 mol L^-1) as well as the presence of l-cysteine on the efficiency of SnH₄ generation by reaction with the NaBH₄ reductant was investigated. Optimal conditions were evaluated in terms of precision, accuracy (by recovery test) and limit of detection. The best results were obtained with l-cysteine and nitric acid for sample acidificitation. Addition of 1 % (m/v) l-cysteine enhanced the Sn signal and expanded the optimal range of HNO₃ concentrations towards higher values; hence, strict control of the acidity could be avoided, up to 1.0 mol L^-1. Under the optimized conditions, a detection limit of 1.2 ng mL^-1 was achieved. The applicability of the proposed method was demonstrated by the determination of low tin contents in digests of fresh and canned tomato samples with satisfactory results.     

Simple and Fast Sample Preparation Procedure Prior to Multi-element Analysis of Slim Teas by ICP OES

The knowledge about mineral content of slim teas is of great importance since the consumption of these beverages has rapidly increased for the past several years. An increasing popularity of these tea products is mainly attributed to their nutritional properties, flavor, taste and health effects. Therefore, the main goal of the present work was to develop a precise and accurate method of the multi-element analysis of slim teas by inductively coupled plasma optical emission spectrometry (ICP OES) without the need for a laborious and tedious sample treatment preceding spectrometric measurements. Five sample preparation procedures, i.e., the total decomposition in a mixture of HNO₃ and H₂O₂ solutions using closed vessel microwave-assisted or open vessel hot-plate systems, the solubilisation in aqua regia or a tetramethyl ammonium hydroxide solution and the extraction in a diluted HNO₃ solution, were compared. The performance of the compared procedures was determined in terms of the precision and the accuracy of results achieved and limits of detection of elements. It was found that the solubilisation in aqua regia gave the best results, i.e., limits of detection between 0.15 and 98.4 ng l^?1, the precision within 0.6?3.0 % and the accuracy better than 5 %. The developed method of the analysis, being a useful alternative to time-consuming wet digestion procedures, was successfully applied to the analysis of five slim tea products.