The operating regularity of the stepper motor of thermal inkjet printers and its application in the China national accreditation service 2017ZO146 altered documents identification proficiency test.

With the continuous innovation of inkjet printing technology, the methods of using inkjet printers for falsification have also constantly evolved, leading to increasing difficulties in identifying printing alterations made by the same inkjet printer. This paper mainly studies the operating regularity of the stepper motor of inkjet printers to determine the operating mechanism of inkjet printers and thus to identify whether documents had been tampered with. To detect the operating track of the stepper motor, 154 documents printed by 22 different brands and models of thermal inkjet printers were studied according to the periodic morphological characteristics of ink marks and the track of the stepper motor during different printing processes.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy.

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically.

Comparison of clozapine in nail and hair of psychiatric patients determined with LC-MS/MS.

As a keratinized material, nail recently has attracting researchers' attention in the pharmaceuticals analysis. There are comparatively limited studies concerning nail's xenobiotic determination and its mechanism. This article reported the development of a sensitive, specific and reproducible LC-MS/MS method, which could be as a foundation of other studies on drug determination in nail.

[Freeze grinding combined ultrasonic technique for the treatment of nail test material].

Objective: To investigate the feasibility of the new method of combining freeze grinding with ultrasonic technique for the pretreatment of the nail for toxicological and pharmaceutical analysis and to compare the advantages and disadvantages of this method with other traditional methods.

Methods: Five pretreatment methods were examined. Scanning electron microscope (SEM) was used to observe the microstructural changes of the nail.

Determination of cocaine and benzoylecgonine in guinea pig's hair after a single dose administration by LC-MS/MS.

A sensitive LC-MS/MS method to determine cocaine and its major metabolite benzoylecgonine in guinea pig' s hair has been established. About 20 mg of decontaminated hair sample was hydrolyzed with 0. 1 mol x L(-1) HCl at 50 degrees C overnight, in the presence of cocaine-d3 and benzoylecgonine-d8 used as internal standards, and then extracted with dichlormethane.

[Simultaneous analyses of cocaine and its metabolite benzoylecgonine in urine by LC-MS/MS].

Objective: To establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of cocaine (COC) and its metabolite benzoylecgonine(BZE) in urine samples.

Methods: A single dose of COC (10 mg/kg) was injected intraperitoneally into guinea pigs and urine samples were collected for 7 days. The urine samples were extracted by auto solid phase extraction (SPE), separated by the Allure PFP propyl column with a mobile phase consisting of methanol and 20 mmol/L ammonium acetate buffer [0.