[Development and evaluation of a chemiluminescence immunoassay for type â procollagen N-terminal peptide].

To develop a magnetic nanoparticle chemiluminescence immunoassay (CLIA) for the determination of type Ⅰ procollagen N-terminal peptide (PINP) in human serum, we expressed a recombinant PINP-α1 protein in Corynebacterium glutamicum and used it as an immunogen to immunize BALB/c mice. We obtained three hybridoma cell lines that stably secret antibody against PINP-α1 protein. After further pairing and screening, we chose a monoclonal antibody 8C12 coupled with biotin as the capture antibody, and a monoclonal antibody 1F11 labeled horseradish peroxidase as the detection antibody. The antibodies combined with the serum samples, forming a sandwich complex which was used to detect the concentration of PINP in serum. After optimizing the conditions, we determined that the best working concentration of the capture antibody and the detection antibody were 3 µg/mL, and the incubation time was 30 minutes. The quantitative assay had a detection range of 5-1 100 ng/mL, with recovery rates between 93%-107% and the minimum detection limit of 1.22 ng/mL achieved. The intra-and inter-assay precisions were lower than 10%. The correlation coefficient of PINP results between this CLIA method and the Roche electrochemiluminescence immunoassay system was 0.906 2. Therefore, this CLIA method is specific and can be used to quantitatively detect the content of PINP in serum, which has the potential to become an auxiliary approach for bone disease examination.

Investigation of Groove Shape Variation during Steel Sheave Spinning.

Large sheaves, such as crosshead sheaves, are foundation parts in the heavy industry. Counter-roller spinning steel sheaves are utilized to replace traditional casting iron parts. Few studies exist on the groove shape of these spinning sheaves. Consequently, it is significant to explore the spinning groove shape variation rule and confirm the appropriate spinning parameters. Both experimental and numerical methods were utilized to study the groove shape variation of Q235 steel sheaves and their results were well matched. Spring-back phenomena were considered in this study. The groove depth was lower than the spinning depth and the last formed groove was the deepest. The former groove depth would be affected by the adjacent following spinning process. The single groove spinning result was linearly dependent on the multiple spinning groove depth. Certain equations were used to calculate the groove depth. The bottom⁻middle⁻top spinning sequence, which was better than other spinning sequences, should be used in the sheave spinning method. A sheave spinning process could be designed based on the study to obtain a fine groove shape.

Metabolism of nitazoxanide in rats, pigs, and chickens: Application of liquid chromatography coupled to hybrid linear ion trap/Orbitrap mass spectrometer.

Nitazoxanide (NTZ) is a nitrothiazole benzamide compound with a broad activity spectrum against parasites, Gram-positive and Gram-negative anaerobic bacteria, and viruses. In this study, hybrid linear ion trap/Orbitrap mass spectrometer providing a high mass resolution and accuracy was used to investigate the metabolism of NTZ in rats, pigs, and chickens. The results revealed that acetylation and glucuronidation were the main metabolic pathways in rats and pigs, whereas acetylation and sulfation were the major metabolic pathways in chickens, which indicated interspecies variations in drug metabolism and elimination. With the accurate mass data and the characteristic MS(n) product ions, we identified six metabolites in which tizoxanide and hydroxylated tizoxanide were phase I metabolites and tizoxanide glucuronide, tizoxanide glucose, tizoxanide sulfate and hydroxyl tizoxanide sulfate were phase II metabolites. Hydroxylated tizoxanide and tizoxanide glucose were identified for the first time. All the comprehensive data were provided to make out the metabolism of NTZ in rats, pigs and chickens more clearly.

[The Effects of Complex of Benzoquinone on Fermi Resonance].

Fermi resonance phenomenon exists in simple compounds and it also widely exists in vibration spectra of complex. The complex can be formed by adding up simple compounds. As a result, the characteristic parameters of some parts of molecule will make changes, and the molecular spectra have a significant change along with it. Benzoquinone and proline in the solution form charge-transfer complex under certain conditions, but the spectra intensity is weak, our research uses Teflon liquid-core optical fiber technology to gain high quality resonance Raman spectra. We acquire Raman spectra of Benzoquinone and its complex in experiments, and analyze the characteristic parameters of Fermi resonance according to J. F. Bertran quantum theory. The results shows that, because of the formation of complex, Fermi resonance peak of C==0 bond shifts to high wavelength, the spectra intensity decreases, the frequency space increases, the coupling coefficient increases. The explanation is that, in the solution of complex, proline is donor, while benzoquinone is acceptor, the non-bonding electron of N atom which is belong to proline transfers to the pi anti-bonding orbital of benzoquinone, then n-pi* charge transfer complex is produced. That causes the change of molecular energy level, changes the Raman spectra. All these researches provide new idea and clue for spectral line certification and attribution of complex molecules, complexes and polymer.

[Determination of cefalonium residue in milk by high performance liquid chromatography-tandem mass spectrometry].

An analytical method was developed for the determination of cefalonium in milk by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A total of 1 g milk was deproteinized by acetonitrile. The supernatant was transferred into a test tube to be blown dry with N2 at 37 degrees C. Then the residue was dissolved with methanol-0.1% formic acid in water (3:7, v/v). The sample was determined by HPLC-MS/MS after the purification. The chromatographic separation was achieved on a C18 column using 0.1% formic acid in water and acetonitrile as mobile phases with gradient elution. Qualitative and quantitative analyses were achieved by HPLC-MS/MS under positive ionization and multiple reaction monitoring (MRM) mode. Matrix-matched calibration curve was used for the quantification. Good correlation coefficients were obtained (r > 0. 999) in the mass concentration range of 2-200 microg/L. The limit of detection (LOD, S/N > or = 3) was 0.5 microg/kg in milk, and the limit of quantification (LOQ, S/N 10) was 2 microg/kg. The mean recoveries at the four levels of LOQ, 1/2MRL (maximum residue level), MRL, 2MRL were between 78.5% and 86.2%, with the intra-day relative standard deviations (RSDs) of 1.5% to 6.2% and inter-day RSDs of 2.9% to 5.6%. In conclusion, the established method can be applied for the determination of cefalonium residue in milk.

[Study of Fermi resonance characteristic of CS2 in THF].

In the present paper, an innovative experiment was done. The authors measured the Raman spectra of CS2 mixed with THF at different volume fractions. According to the J. F. Bertran theory, we analyzed the changing regularity of v1-2v2 Fermi resonance along with the different concentration. It was shown that the characteristic parameters of Fermi resonance in solution, such as spectra intensity, frequency space, coupling coefficient and anharmonic constant, will make changes along with solution concentration variation. Because of the existing of solvent effects, the spectra intensity decreases gradually, and the coupling coefficient increases gradually. The explanation of such changes is that the vibration spectra are affected not only by scattering coefficient, but also by more weak hydrogen bond's formation. In addition, the asymmetric frequency shift of the Raman spectra was also found in the paper. The fundamental frequency v1 basically has no shifts, but the overtone frequency 2v2 moves towards the high wave number gradually, which is inconsistent with the theory of symmetrical movement. According to the study of molecular microcosmic action, the formation and mechanism of the weak hydrogen bond can preferably explain the above phenomenon. The research has a major influence on the further study of solvent effects in Fermi resonance. And the paper will also provide certain reference value for the study of molecule vibration spectra in solution.