Method of reference samples preparation for X-ray fluorescence analysis.

The study focuses on the development of a new procedure for the preparation of reference samples with a given concentration for X-ray fluorescence analysis by adding certain volume of analyzed elements solutions with a known concentration to certified reference rock materials and further fusion with borate fluxes. The presented method of preparing emitters allows not only to obtain samples with the required concentrations for the elements to be determined, but also to preserve the influence that other elements have on the analytical signal. A set of 12 certified reference samples of rocks was used to construct calibration dependencies. The preparation of multicomponent modified reference samples (MRS) was carried out on the basis of certified reference materials (CRM) included in the set for constructing calibration curves. The concentration dependences on the analytical signal were established for the main oxides (SiO2, TiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5) and minor elements (Cr, Cu, Ba, Ni, Sr, V, Zr, and Zn) using an X-ray fluorescence spectrometer with wavelength dispersion. With the help of modified reference samples, the calibration curves were expanded and supplemented both for major oxides (P2O5, MnO) and for minor elements (Zn, Sr). Also, in the course of the research, a comparison was made of the homogeneity of the emitters obtained according to the MRS preparation procedure presented in the work and reference samples (RS) made of CRM prepared according to the standard method for rocks, and the composition of inclusions on the surface of the fused disks was determined.

The Impact of Platelet Isolation Protocol on the Release of Extracellular Vesicles.

BACKGROUND: Platelet-derived extracellular vesicles (PEVs) are small vesicles released by activated platelets that are gaining growing interest in the field of vascular biology. The mode of platelet activation is a critical determinant of PEVs release, phenotype and function. However, only very limited information is available concerning the impact of the platelet purification procedure on PEVs release. METHODS: Washed or isolated platelets were separated by differential centrifugations. For washed platelets, the platelet pellet was washed by resuspension in PIPES buffer and finally resuspended in HEPES buffer. Isolated platelets were obtained by directly resuspending the platelet pellet in HEPES, skipping the washing steps in PIPES buffer. PEVs release was induced in washed or isolated platelets by stimulation with different agonist and analysed by Nanoparticle Tracking Analysis. RESULTS: Isolated platelets showed a higher release of PEVs upon adenosine diphosphate (ADP) stimulation compared to washed platelets, whereas PEVs released upon stimulation with strong agonists (thrombin, collagen, A23187, U46619) were similar in the two groups. This different responsiveness to ADP was also observed as a higher α-granules release and protein kinase C activation in isolated platelets compared to washed ones. Residual plasma contamination appeared to be essential for the ability of platelets to release PEVs in response to ADP. CONCLUSIONS: In conclusion, our study strongly suggests that procedure adopted for platelets preparation is a critical determinant of PEVs release upon ADP stimulation.

Current and potential use of fresh frozen cadaver in surgical training and anatomical education.

As surgical procedures continue to be more complex, the need for more effective training in anatomy has increased. The study of anatomy plays a significant role in the understanding of the human body as well as in basic and advanced clinical training. Among the different cadaver models, fresh frozen cadavers (FFCs) are known for their realistic tissue quality. The purpose of this article was to review and summarize the preparation procedures for and reported cases involving FFCs. PubMed, Scopus, Medline, and Web of Science were searched for relevant studies. The preparation procedures were divided into five steps: washing, irrigation, freezing, defrosting, and arterial infusion. Not all steps were reported to be mandatory, but omitting one or more could result in a loss of quality. FFCs were reported to be used for various purposes: undergraduate education, general surgery training, vascular surgery training, minimal access surgery (laparoscopic surgery) training, and microsurgery training. In all categories, expert opinions and statistical analyses indicated successful outcomes. The reasons for high satisfaction with FFCs included realistic texture, capability of reenacting actual operations, and accuracy of anatomical locations. The results also revealed the importance and advantages of the dissection courses in surgical training. Since the direct comparison between cadaver models is insufficient, future studies regarding this topic are deemed necessary. In addition, it would be advantageous to develop methods to improve FFC quality, or ideas to optimize this model for certain purposes.

Preparation of Antihypertensive Drugs in Biological Matrix with Solvent Front Position Extraction for LC-MS/MS Analysis.

Solvent front position extraction procedure was used to prepare biological samples containing selected antihypertensive drugs (ramipril, lercanidipine, indapamide, valsartan, hydrochlorothiazide, perindopril, and nebivolol). Substances separated from the biological matrix components (bovine serum albumin) were quantified by means of liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Sample preparation process was performed with the use of a prototype horizontal chamber with a moving pipette driven by a 3D printer mechanism enabling a controlled eluent flow velocity. Application of this device was advantageous for simultaneous preparation of several samples for further quantitative analysis, with a synchronized reduction of manual operations and solvent consumption. Quantitative results obtained for the majority of the investigated antihypertensive drugs in a complex biological matrix were satisfactory. The values of the %RSD were around 5% for six of the seven substances (with the exception of indapamide). The method exhibits a suitable accuracy (the relative error percentage was below 10% for most drugs). The values of LOD and LOQ were in the range of 1.19 µg/L-8.53 µg/L and 3.61 µg/L-25.8 µg/L, respectively.

Comparative Study of Three Mixing Methods in Fusion Technique for Determining Major and Minor Elements Using Wavelength Dispersive X-ray Fluorescence Spectroscopy.

Accurate analysis using a simple and rapid procedure is always the most important pursuit of analytical chemists. In this study, a new sample preparation procedure, namely the shaker cup (SH) method, was designed and compared with two sample preparation procedures, commonly used in the laboratory, from three aspects: homogeneity of the sample-flux mixture, potential for sample contamination, and sample preparation time. For the three methods, a set of 54 certified reference materials (CRMs) was used to establish the calibration curves, while another set of 19 CRMs was measured to validate the results. In the calibration procedures, the matrix effects were corrected using the theoretical alpha coefficient method combined with the experimental coefficient method. The data of the major oxides (SiO2, TiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) and minor elements (Cr, Cu, Ba, Ni, Sr, V, Zr, and Zn) obtained by wavelength dispersive X-ray fluorescence spectroscopy (WD-XRF) were compared using two derivative equations based on the findings by Laurence Whitty-Léveillé. The results revealed that the WD-XRF measured values using the SH method best agreed with the values recommended in the literature.

Optimization of the procedure of solvent front position extraction for preparation of multi-component sample for instrumental analysis.

Solvent Front Position Extraction (SFPE) procedure has been recently introduced as a novel concept for multi-component sample preparation. According to the procedure, thin-layer chromatography (TLC) is used to separate the compounds of interest from matrix components, and to focus them into a common zone from which the compounds are extracted and transferred to apparatus for instrumental analysis. In the paper, we investigate different adsorbent types of the chromatographic plates and various mobile phases, including pH of their buffers, in respect of optimization conditions of the SFPE procedure. The research was carried out using a test sample containing 9 compounds characterised by different chemical properties, hence the conclusions from the obtained results can be applied to other multi-component samples. Under the optimal conditions, all target compounds are separated from other compounds (matrix), and evenly distributed along a narrow strip, which is advantageous for their quantitation. The determination results are good, the percentage values of relative error and relative standard deviation do not exceed 6%.

Azo coupling-based derivatization method for high-sensitivity liquid chromatography-tandem mass spectrometry analysis of tetrahydrocannabinol and other aromatic compounds.

An azo coupling-based derivatization method is reported for high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantitation of tetrahydrocannabinol (THC) and other aromatic compounds, i.e. phenols and amines. Through the azo coupling of a diazonium to an analyte, it produces a derivatized analyte which has enhanced ionization efficiency and results in high-response fragments in tandem mass spectrometry. The derivatization method was applied to six typical aromatic compounds using three different diazonium salts as derivatization reagents, demonstrating its applicability to a variety of analytes and reagents. The derivatization reaction can be directly carried out in neat samples, and after derivatization the samples can be immediately sent to the LC-MS/MS instrument for analysis. These advantages facilitate a one-step sample preparation procedure that can be completed in less than one hour, allowing for a "derivatize & shoot" lab workflow. The derivatization method was applied to establish an LC-MS/MS assay for the quantitation of THC in human breath samples. The derivatization conditions were studied in this application, including the effects of acidity, organic solvent, and diazonium concentration in the reaction. The THC derivatization assay was validated and achieved a limit of quantitation (LOQ) of 0.50 pg/ml using either of the two regio-isomers of the azo-derivative of THC (THC-DRV). To prove that the derivatization method has compatibility with complex-matrix samples, a THC derivatization assay for serum samples was established, in which the azo coupling reaction was directly carried out in crude protein-precipitated supernatants. An LOQ of 5.0 pg/ml was achieved. In addition, excellent correlation between THC derivatization and non-derivatization assays was found in the analysis of whole blood samples.

Development of a new method for the preparation of an acellular allodermis, quality control and cytotoxicity testing.

Demand for use of acellular allodermis is high but commercially appropriate products are not used routinely because of very high price and limited availability. These facts did motivate us to prepare acellular allodermis using a new, simple and less expensive method. We have developed a original method for preparation of acellular allogeneic dermis based on action of a proteolytic enzyme in combination with distilled water. Hypotonic environment in comparison with SDS or Triton ansure no toxicity of the final product. Trials for determination of optimal trypsin concentrations, temperature and time of action were performed. According to our results, the use of 2.5% trypsin/EDTA solution overnight at +4 °C was proving to be optimal. The histology confirmed absence of cells in the prepared dermis. No toxicity of final acellular dermis was confirmed by three independent tests (agar diffusion test contact cytotoxicity test and grow curve). The prepared acellular dermis seems to be suitable not only for direct clinical use, but it can be used as a scaffold for cell cultivation as well.

Soy-Based Adhesive Cross-Linked by Phenol-Formaldehyde-Glutaraldehyde.

To prepare a low-formaldehyde soy-based adhesive with good water resistance, phenol-formaldehyde modified with glutaraldehyde (PFG) with lower free phenol and free formaldehyde contents was used to cross-link the soy-based adhesive. The results showed that the mechanical properties and water resistance of plywood prepared with soy-based adhesive with PFG was better than that of plywood with the same amount of phenol-formaldehyde (PF). The reaction between phenol and glutaraldehyde was proved by 13C-NMR. Under the optimized preparation conditions for plywood, that is to say, press temperature 160 °C, press time 4 min and resin loading 320 g·m-2, type I plywood could be prepared with 9% PFG as a cross-linker of soy-based adhesive. The Differential Scanning Calorimetry (DSC) result confirmed the cross-linking reaction between soy-based adhesive and PFG or PF. The activation energy of soy-based adhesive with cross-linker PFG was higher than that with PF resin.

Study on Preparation Procedure of Pediatric Kechuan Black Plasters / 中国药师

Objective:To explore the preparation procedure of pediatric Kechuan black plasters. Methods:A single factor method was used to observe and study the preparation process of pediatric Kechuan black plaster from the following aspects: the selection of matrix raw material and refined equipment, and the temperature of refinery, “Xiadan”, pouring white wax and adding fine material powder in production processing. Results:The best temperature of“Xiadan” for pure sesame oil and mineral orange with the purity a-bove 95% was 313 ℃. The “Xianzha” temperature was 264 ℃, the temperature of “Houxia” was between 180 ℃ and 200 ℃, and white wax instead of the traditional method was used to eliminate fire toxin. Conclusion:The research is helpful to improving the quali-ty of the black plasters. The preparation process is stable and feasible, and suitable for the industrial production.

Enhanced bactericidal action of acidified sodium chlorite caused by the saturation of reactants.

AIMS: Factors affecting the antibacterial action of acidified sodium chlorite (ASC), a widely used disinfectant, have not been determined. This study investigated the significant factors suggesting efficient production method to maximize bactericidal action of ASC. METHODS AND RESULTS: The effects of (i) preparation procedures (total three methods); (ii) initial concentrations of reactants: sodium chlorite (SC) and citric acid (CTA) (up to maximum solubility of each reactant) and (iii) final pH values (3·0 and 2·5) to the bactericidal action of ASC were investigated with a fixed final concentration of SC (10 ppm) using various foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus). The antimicrobial compounds produced and the bactericidal effects depended on the preparation procedure and the initial concentrations of the reactants. The ASC prepared by premixing highly concentrated reactants (in particular > 40%) followed by dilution (dilution after reaction, DAR) was more effective in inactivating foodborne pathogens, and it produced higher antimicrobial compound (Cl(2) and ClO(2)) yields than the other procedures. A 5-min treatment with ASC, produced using the other procedures, resulted in a reduction of < 3·5 log CFU ml(-1) (Gram positive = 0·18-0·78; Gram negative = 0·03-3·49 log CFU ml(-1)), whereas ASC produced with the DAR procedure using the saturated reactants completely inactivated all of the test pathogens within 5 min without recovery (initial concentration = 6·94-7·08 log CFU ml(-1)). CONCLUSION: The ASC production with the DAR procedure using the saturated reactants maximizes both the antimicrobial compound yields and bactericidal effects of the ASC solutions. SIGNIFICANCE AND IMPACT OF THE STUDY: This study will contribute to increase the efficiency of ASC treatments for disinfections reducing the effective SC concentrations for industrial use.

Preparation and quality control of methyl salicylate glycoside tablets / 中国药学杂志

OBJECTIVE: To establish the method of the preparation and test for methyl salicylate glycoside (MSG) tablets. METHODS: MSG tablets were prepared with MSG as main drug and microcrystalline cellulose and sodium carboxymethyl starch as exipients. Its detection method was studied. RESULTS: After experimental study, the high performance liquid chromatography method for related substances detection and content determination of MSG tablets were established. CONCLUSION: The prescription is reasonable and the preparation technology is reliable. The HPLC method has high accuracy and sensitivity and can be used for MSG tablets test.

Optimization of Extracting Technology of Jiejiu Gankang Granules by Orthogonal Design / 中国中医药信息杂志

Objective To study the extraction process of Jiejiu Gankang granules by orthogonal test.Methods With the ethanol extraction rates of the medical materials like ginseng,radix salviae miltiorrhizae,the water extraction rates of the medical materials like hawthorn,and Tanshinone ⅡA as the parameters,the extract conditions of Jiejiu Gankang granules was optimized by orthogonal design.Results The optimal preparation process was as follows:the mixture of medical materials like ginseng and Schisandra chinensis was refluxed twice with total 10 times of 70% alcohol,2.0 hours for each time,and then the mixture of medical materials like hawthorn extracted twice with total 10 times of boiling water,2.0 hours for each time.Conclusion The optimal preparation process is reasonable and with high extraction rate of active components.

Study on Preparation Process of Fangji Huangqi Granules / 中药新药与临床药理

Objective To optimize the preparation process for Fangji Huangqi Granules. Methods With the extraction rates of tetrandrine, fanchinoline, astragaloside Ⅳand solid as the parameters, the extract conditions of Fangji Huangqi Granules were optimized by orthogonal design . Then the anti-inflammation effect of the extracts was observed on the mice and rats. Results The optimal preparation process was as follows:the mixture of medical materials was firstly refluxed twice with total 10 times of 70 %alcohol,1.5 hours for each time, and then extracted twice with total 12 times of boiling water ,1.5 hours for each time. The anti-inflammation effect of the extracts was obvious on the mice and rats. Conclusion The optimal preparation process is reasonable and with high extraction rate of active components.

Optimum Selection of Preparation Procedure of Sanhuangweixueping Capsules / 中成药

Objective: To select the optimum prepartion procedure for Sanhuangweixueping, Capsules. Methods: The optimum conditions were selected with the contents of active components: emodin, berberine, and baicalin as markers. Results: The optimum preparation procedure was: berberine was extracted with 95% alcohol. Rhizoma Bletillae was immersed with water, then precipitated with 70% alcohol. Radix et Rhizoma Rhei, Radix Scutellariae and Radix Glycyrrhizae were decocted, then precipitaed with 60% alcohol. Sanhuangweixueping Capsules prepared with the optimum preparation procedure possessed stronger pharmacological effect. Conclusion: The optimum prepartion procedure is reliable and the extraction ratio of active compoents is high.

Study on Preparation Procedure of Grub Eye Drops / 中成药

Objective: To establish the optimum preparation procedure for Grub Eye Drops. Methods: The amount of extract abtained from extraction solutions, the contents of glutamic acid and glycine, nitrogen content and TLC spots were used to evaluate the extraction procedure for Grub Eye Drops by orthogonal design. Results: The optimum extraction condition was A 3B 2C 1. That is adding ten times amount of water to soaking for 30min, decocting for 1.5h, filtering to obtain filtrate Ⅰ, adding seven times of water into filter residue, decocting for 1h to obtain filtrate Ⅱ, combining filtrate Ⅰ and Ⅱ. Conclusion: The experimental method is suitable for the productive preparation of Grub Eye Drops.