A method of identifying the blood contributor in mixture stains through detecting blood-specific mRNA polymorphism

In the past decades, messenger RNA (mRNA) biomarkers have been employed to identify the origin of body fluids in forensic medicine. We hypothesized that the polymorphism of mRNA could be applied to identify individuals in mixture samples composed of two body fluids. In this study, we selected five blood-specific mRNA biomarkers of venous blood (SPTB, CD3G, AMICA1, ANK1, and GYPA) that encompass 16 SNPs to identify the mixture contributor(s). Five specific gene markers for menstrual blood, semen, skin, saliva, and vaginal secretions were amplified and typed as body-fluid positive controls. We established the system of multiplex PCR and single base extension (SBE) reaction followed by CE. The amplicon size was between 90bp and 294bp. The peripheral blood specificity was examined against other human body fluids, including saliva, semen, skin, menstrual blood, and vaginal secretion. The 16 SNPs were peripheral blood specific and could be successfully typed in homemade mixtures which are composed of different body fluids with 1 ng peripheral blood mRNA added. This system showed a supersensitivity (1:100) in detecting the trace amount of peripheral blood mixed in other body fluids and a combined discrimination power (CDP) of 0.99929 in Chinese population. It was the first time to establish a method for identifying the blood donors and deconvoluting mixtures through detecting mRNA polymorphism with SNaPshot assay. This peripheral blood specific SNP typing system showed high sensitivity to the typing of blood source specific markers regardless of other body fluids in the mixture.     

A novel model for quantification of the moisture absorption of polymeric laminated composites

In the present study, a new model was developed that considers the amount of the environmental fluid absorption by different constituents of polymeric laminated composites including fibers, resin, fiber-matrix interphase region, ply interface region, and voids. By knowing the fluid absorption behavior of the composite constituents, the present model can predict the amount of fluid absorption of different constituents of polymeric laminated composites with an arbitrary resin volume fraction and stacking sequence. Test specimens were fabricated by glass fibers and vinyl ester resin. The environmental fluids, examined in this study, were distilled and saline water under different temperatures and salt concentrations. To investigate the absorption behavior of different constituents of polymeric composite, various tests were conducted on fibers, pure cured resin, unidirectional composite specimens, and laminated composites. Based on the results of the tests, a new theoretical model was developed to quantify and predict the amount of fluid absorption of different constituents of laminated polymeric composites. The thickness of the interphase region between the fiber and matrix was also measured using the scanning electron microscope (SEM) images and nano-indentation tests. The consistency of experimental results with the outcomes of the theoretical model indicates the accuracy of the model.     

Synthesis of Supported Heterogeneous Catalysts by Laser Ablation of Metallic Palladium in Supercritical Carbon Dioxide Medium

To obtain a supported heterogeneous catalyst, laser ablation of metallic palladium in supercritical carbon dioxide was performed in the presence of a carrier, microparticles of γ-alumina. The influence of the ablation process conditions—including supercritical fluid density, ablation, mixing time of the mixture, and laser wavelength—on the completeness and efficiency of the deposition of palladium particles on the surface of the carrier was studied. The obtained composites were investigated by scanning and transmission electron microscopy using energy dispersive spectroscopy. We found that palladium particles were nanosized and had a narrow size distribution (2–8 nm). The synthesized composites revealed high activity as catalysts in the liquid-phase hydrogenation of diphenylacetylene.     

Polycaprolactone solution–based ink for designing microfluidic channels on paper via 3D printing platform for biosensing application

This work reports a novel fabrication technique for development of channels on paper‐based microfluidic devices using the syringe module of a 3D printing syringe–based system. In this study, printing using polycaprolactone (PCL)‐based ink (Mw 70 000‐90 000) was employed for the generation of functional hydrophobic barriers on Whatman qualitative filter paper grade 1 (approximate thickness of 180 μm and pore diameter of 11 μm), which would effectively channelize fluid flow to multiple assay zones dedicated for different analyte detection on a microfluidic paper‐based analytical device (μPAD). The standardization studies reveal that a functional hydrophilic channel for sample conduction fabricated using the reported technique can be as narrow as 460.7 ± 20 μm and a functional hydrophobic barrier can be of any width with a lower limit of about 982.2 ± 142.75 μm when a minimum number of two layers of the ink is extruded onto paper. A comparison with the hydrodynamic model established for writing with ink is used to explain the width of the line printed by this system. A fluid flow analysis through a single channel system was also carried out to establish its conformity with the Washburn model, which governs the fluid flow in two‐dimensional μPAD. The presented fabrication technique proves to be a robust strategy that effectively taps the advantages of this 3D printing technique in the production of μPADs with enhanced speed and reproducibility.     

Method development and validation for the determination of biogenic amines in soy sauce using supercritical fluid chromatography coupled with single quadrupole mass spectrometry

Biogenic amines have been reported in many foods such as fish, meat, and soy sauce. The consumption of foods containing high concentrations of biogenic amines has been associated with health hazards. In this study, a green and efficient method using supercritical fluid chromatography coupled with single quadrupole mass spectrometry was developed for determination of biogenic amines in soy sauce. The chromatographic and mass spectrometry conditions were systematically optimized in terms of selectivity and peak shape. Nine biogenic amines were well separated within 25 min on a Cosmosil 5HP column using 5% (v/v) water and 0.2% (v/v) ammonia solution in methanol as mobile phase additives at a backpressure of 120 bar and temperature of 40°C. The established method was fully validated regarding the linearity, sensitivity, precision, and accuracy. The limits of detection and limits of quantification ranged from 0.03 to 10.50 μg/mL and 0.10 to 23.1 μg/mL, respectively. The relative standard deviations for intra‐ and interday precisions were all lower than 9.36% and the recoveries ranged from 75.82 to 99.63% and 80.10 to 99.89% for two levels of standards spiked in soy sauce, respectively. Finally, the established method was successfully applied to the quantitative analysis of biogenic amines in soy sauce.     

Investigation of dense slurry suspensions with coaxial mixers: Influences of design variables through tomography and mathematical modelling

The coaxial mixers enhance the suspension of concentrated slurries in an agitated reactor. In this research work, the complex slurry suspension and dissemination behavior in a coaxial slurry mixing system (comprised of a close clearance anchor rotating with a low speed and an inner axial impeller rotating with a high speed) was analyzed employing ERT (electrical resistance tomography, a non-intrusive flow visualization technique), and computational fluid dynamics (CFD). The numerical models were validated by comparing the axial solid concentration profiles generated using the ERT data and the CFD simulation results. The influences of various important parameters such as the diameter of the inner axial impeller, the inner impeller type, and the inner impeller spacing on the hydrodynamic characteristics of the slurry suspensions in a coaxial mixing vessel were thoroughly analyzed. The radial and axial velocity profiles of solid particles were generated using the validated mathematical models. The assessment of energy loss due to the solid–solid collisions, the particle–fluid frictions, and the particle–vessel wall collisions was conducted. The evaluation of optimum inner impeller clearance and inner impeller diameter is essential to attain a high degree of solids suspension and dissemination in a coaxial slurry mixing system.     

Stress-enhanced transport of toluene in poly aryl ether ether ketone (PEEK)

The transport of fluids in the semicrystalline polymer, poly(aryl ether ether ketone) (PEEK), was investigated. Both solubility and rate of penetration of toluene into PEEK are markedly increased by the application of an external stress. The induction period (i.e., the time for the sorption to begin) is a function of applied stress as well as temperature and crystallinity. At 22°C in 29% crystalline PEEK the induction period was reduced from more than 2000 h to approximately 10 h whereas the solubility of toluene was increased from 9 to 44 wt % upon the application of an external tensile stress of 30 MPa. A critical stress (i.e., a stress value below which the stress-enhanced effects are not observed) was determined. The critical stress is a strong function of crystallinity and temperature. © 1996 John Wiley & Sons, Inc.     

METHOD–OF–LINES SOLUTION OF TIME–DEPENDENT TWO–DIMENSIONAL NAVIER–STOKES EQUATIONS

A novel approach to the development of a code for the solution of the time-dependent two-dimensional Navier–Stokes equations is described. The code involves coupling between the method of lines (MOL) for the solution of partial differential equations and a parabolic algorithm which removes the necessity of iterative solution on pressure and solution of a Poisson-type equation for the pressure. The code is applied to a test problem involving the solution of transient laminar flow in a short pipe for an incompressible Newtonian fluid. Comparisons show that the MOL solutions are in good agreement with the previously reported values. The proposed method described in this paper demonstrates the ease with which the Navier–Stokes equations can be solved in an accurate manner using sophisticated numerical algorithms for the solution of ordinary differential equations (ODEs).