Spectrophotometric determination of metal ions in electroplating solutions in the presence of EDTA with the aid of multivariate calibration and artificial neural networks

Metal ions such as Co(II), Ni(II), Cu(II), Fe(III) and Cr(III), which are commonly present in electroplating baths at high concentrations, were analysed simultaneously by a spectrophotometric method modified by the inclusion of the ethylenediaminetetraacetate (EDTA) solution as a chromogenic reagent. The prediction of the metal ion concentrations was facilitated by the use of an orthogonal array design to build a calibration data set consisting of absorption spectra collected in the 370-760 nm range from solution mixtures containing the five metal ions earlier. With the aid of this data set, calibration models were built based on 10 different chemometrics methods such as classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), artificial neural networks (ANN) and others. These were tested with the use of a validation data set constructed from synthetic solutions of the five metal ions. The analytical performance of these chemometrics methods were characterized by relative prediction errors and recoveries (%). On the basis of these results, the computational methods were ranked according to their performances using the multi-criteria decision making procedures preference ranking organization method for enrichment evaluation (PROMETHEE) and geometrical analysis for interactive aid (GAIA). PLS and PCR models applied to the spectral data matrix that used the first derivative pre-treatment were the preferred methods. They together with ANN-radial basis function (RBF) and PLS were applied for analysis of results from some typical industrial samples analysed by the EDTA-spectrophotometric method described. DPLS, DPCR and the ANN-RBF chemometrics methods performed particularly well especially when compared with some target values provided by industry.     

A 21st century technique for food control: Electronic noses

This work examines the main features of modern electronic noses (e-noses) and their most important applications in food control in this new century. The three components of an electronic nose (sample handling system, detection system, and data processing system) are described. Special attention is devoted to the promising mass spectrometry based e-noses, due to their advantages over the more classical gas sensors. Applications described include process monitoring, shelf-life investigation, freshness evaluation, authenticity assessment, as well as other general aspects of the utilization of electronic noses in food control. Finally, some interesting remarks concerning the strengths and weaknesses of electronic noses in food control are also mentioned.     

Evaluation of biodiesel-diesel blends quality using H NMR and chemometrics

In this work, the use of ¹H NMR spectroscopy and statistical approach to the evaluation of biodiesel-diesel blends quality is described. Forty-six mixtures of oil-diesel, biodiesel-diesel, and oil-biodiesel-diesel were analyzed by ¹H NMR and such data were employed to design four predictive models. Thirty-six mixtures were used in the calibration set and the others in the validation. The PCR and PLS models were evaluated through statistical parameters.Briefly, PLS and PCR models were suitable for the prediction of biodiesel and oil concentration in mineral diesel. Specially, in higher concentration the predicted values were quite similar to the real ones. This fact was evidenced by the low relative errors of high concentrated samples; this means that the prediction of low concentrated samples will probably show high deviation. Therefore, ¹H NMR-PLS and ¹H NMR-PCR methods are fairly useful for the quality control of biodiesel-diesel blends, particularly they are suitable for prediction of concentrations greater than 2%.     

Covalent Interaction of Ru(terpy)(tmephen)Cl+ with DNA: A Potential Ruthenium‐Based Anticancer Drug

The use of ruthenium complexes in antitumor therapy was launched two decades ago. In view of their low toxicity and good selectivity for solid tumor metastasis, ruthenium complexes have great potential as alternative drugs to cisplatin in cancer chemotherapy. A series of monochloro ruthenium complexes, Ru(terpy) (NN)Cl⁺ (NN, bidentate nitrogen ligand), containing different electron‐donating groups were prepared. The reactivity towards the formation of Ru‐DNA adduct were revealed by gel mobility shift assay. Their DNA binding sites of Ru(terpy)(tmephen)Cl⁺ were located predominantly at the purine residues i.e., guanine and adenine, by terminating DNA elongation in vitro using PCR and primer extension techniques. Surprisingly, the ability of Ru(terpy)(tmephen)Cl⁺ to inhibit cell growth was found to be approximately two times better than that of a known cross‐linking agent, Ru(bpy)₂Cl₂. Therefore, the increase in liability of the chloro ligand was demonstrated to improve the reactivity of these ruthenium complexes towards the covalent bond formation in Ru‐DNA adducts and result also in a significant inhibition of cell growth. Based on our results, these ruthenium complexes modified with electron‐rich groups provide new consideration in the tune of ruthenium‐based drugs in cancer chemotherapy.     

Microchip PCR

Miniaturization of genetic tests has become an important goal. This review surveys the current progress towards the miniaturization of tests based on the polymerase chain reaction (PCR). It examines the different types of PCR microchip designs, fabrication methods,and the components of a microchip PCR device. It also discusses the problems attributable to surface chemistry of microchip components (inhibition of PCR), and the static and dynamic surface passivation strategies developed for the solution of these difficulties     

Altered expression of insulins I and II and their mRNAs in the islets of Langerhans in dexamethasone-induced diabetic rats

Rats have two isomeric insulins (insulins I and II). There have been no reports on the expression of the isomeric insulins in glucocorticoid-induced diabetic rats. To clarify the relation of the expression of each insulin and its mRNAs in dexamethasone-induced diabetic rats, the amounts of the isomeric insulins and mRNAs in the islets of Langerhans were determined in vivo and in vitro. A sensitive and selective HPLC-fluorescence determination method for the isomeric insulins and a newly developed real-time quantitative RT-PCR method for their mRNAs were used. There was a greater reduction of insulin II than insulin I in the islets of Langerhans in dexamethasone-induced diabetic rats. This alteration may be caused by a disproportionate expression of the respective mRNA for the isomeric insulins that resulted from the direct effect of dexamethasone. In addition, continuous hyperglycemia may also suppress the expression of the insulin II mRNA. The overall effects of dexamethasone and hyperglycemia may cause a greater reduction of insulin II than insulin I in the dexamethasone-induced diabetic rat. Conversely, an elevated ratio of insulin I to II in the islets could suggest a diabetic condition.     

Successful direct amplification of nuclear markers from single dog hairs using DogFiler multiplex

We report on successful amplification of canine STR DNA profiles from single dog hairs. Dog hairs are commonly found on clothing or items of interest in forensic casework and may be crucial associative evidence if linked to an individual dog. We used direct amplification from these hairs to increase the DNA yield of the sample, as well as greatly reducing analysis time. Hairs from different somatic regions were used from several different dog breeds to amplify a selection of eight loci from the validated DogFiler multiplex. Naturally shed canine hairs were processed, with a mix of coarse topcoat (guard) hairs and thinner soft undercoat hairs. Multiple sections of single hairs were amplified in 5 mm segments to determine the viability of DNA recovery from the shaft of the hair. Single guard hairs were cut into 5 mm sections and added directly into a PCR tube. Undercoat hairs, which are very fine, were amplified together in a single tube (approximately ten small hairs). Coarse hairs were found to be the most successful in producing full DNA profiles at all eight loci, matching the corresponding reference profile for that dog.     

人干细胞生长因子的克隆与表达

干细胞生长因子能够刺激激造血干细胞生长，并与多种细胞因子有协同作用。研究中，运用ＰＣＲ手段，从中国人胎肝ｍＲＮＡ中扩增得到编码人ＳＣＦ全部胞外部分的ｃＤＮＡ。经测序鉴定后，将其克隆人表达载体ｐＲＳＥＴ－Ｃ，并在大肠杆菌ＤＥ３菌株进行表达。     

Genotyping of single nucleotide polymorphism in MDM2 genes by universal fluorescence primer PCR and capillary electrophoresis

Single nucleotide polymorphism (SNP) 309 in the promoter region of the murine double minute 2 (MDM2) gene plays an important role in human tumorigenesis. We established a simple and effective CE method for SNP detection in the MDM2 gene. We designed one universal fluorescence-based nonhuman-sequence primer and one fragment-oriented primer, which were combined in one tube, and proceeded with the polymerase chain reaction (PCR). The amplicons were analyzed by capillary electrophoresis using single-strand conformation polymorphism method. PCR fragments generated from this two-in-one PCR displayed either T/T or G/G homozygosity or T/G heterozygosity. A total of 304 samples were blindly genotyped using this developed method, which included the DNA from 138 healthy volunteers, 43 chronic myeloid leukemia (CML) patients, and 123 colorectal cancer (CRC) patients. The results were confirmed by DNA sequencing and showed good agreement. The SSCP-CE method was feasible for SNP screening of MDM2 in large populations.