Transport Of Biological Material Research Articles

Simple and rapid analysis of Linagliptin in dried blood spot using an ionic liquid based vortex‐assisted dispersive liquid–liquid microextraction coupled with liquid chromatography–electrospray ionization–tandem mass spectrometry: Application to pharmacokinetic studies

AbstractA simple, rapid, and convenient ionic liquid based vortex‐assisted dispersive liquid–liquid micro extraction method for the determination of Linagliptin was developed. The main novelty of the present work deals with the analysis of Linagliptin in dried blood spot with significant advantages with regard to invasive sampling, volume of blood used (< 20 μL), storage and transport of biological materials and requirements for special biohazard arrangements. The extraction sample was assayed using liquid chromatography–tandem mass spectrometry using electropray ionization techniques. The effects of significant factors in extracting and disperser solvent, and salt contents were investigated. An efficient quantification method was developed for bioassay of Linagliptin using Sitagliptin as internal standard through Inertsil ODS‐3V (250 mm × 4.6 mm, 5 μm) column using 10 mM ammonium acetate buffer (pH adjusted to 4.6 with 0.1% Trifluoroacetic acid): Acetonitrile [10:90 (v/v)] as mobile phase. Tandem mass spectrometry detection was performed to monitor precursor → product ion transitions m/z 473.3 → 364.2 for Linagliptin, m/z 408.2 → 235.1 for internal standard. The assay was linear from 6 to 1500 ng/mL and the mean recoveries are more than 90%. The peak dried blood spot concentration (Cmax) after 1.5 h was determined to be 1391.2 ng/ml for Linagliptin.

Effects of Wave-Induced Processes in a Coupled Wave–Ocean Model on Particle Transport Simulations

This study investigates the effects of wind–wave processes in a coupled wave–ocean circulation model on Lagrangian transport simulations. Drifters deployed in the southern North Sea from May to June 2015 are used. The Eulerian currents are obtained by simulation from the coupled circulation model (NEMO) and the wave model (WAM), as well as a stand-alone NEMO circulation model. The wave–current interaction processes are the momentum and energy sea state dependent fluxes, wave-induced mixing and Stokes–Coriolis forcing. The Lagrangian transport model sensitivity to these wave-induced processes in NEMO is quantified using a particle drift model. Wind waves act as a reservoir for energy and momentum. In the coupled wave–ocean circulation model, the momentum that is transferred into the ocean model is considered as a fraction of the total flux that goes directly to the currents plus the momentum lost from wave dissipation. Additional sensitivity studies are performed to assess the potential contribution of windage on the Lagrangian model performance. Wave-induced drift is found to significantly affect the particle transport in the upper ocean. The skill of particle transport simulations depends on wave–ocean circulation interaction processes. The model simulations were assessed using drifter and high-frequency (HF) radar observations. The analysis of the model reveals that Eulerian currents produced by introducing wave-induced parameterization into the ocean model are essential for improving particle transport simulations. The results show that coupled wave–circulation models may improve transport simulations of marine litter, oil spills, larval drift or transport of biological materials.

Stochastic fluid dynamics simulations of the velocity distribution in protoplasmic streaming

Protoplasmic streaming in plant cells is directly visible in the cases of Chara corallina and Nitella flexilis, and this streaming is understood to play a role in the transport of biological materials. For this reason, related studies have focused on molecular transportation from a fluid mechanics viewpoint. However, the experimentally observed distribution of the velocity along the flow direction x, which exhibits two peaks at Vx = 0 and at a finite Vx(≠0), remains to be studied. In this paper, we numerically study whether this behavior of the flow field can be simulated by a 2D stochastic Navier–Stokes (NS) equation for Couette flow in which a random Brownian force is assumed. We present the first numerical evidence that these peaks are reproduced by the stochastic NS equation, which implies that the Brownian motion of the fluid particles plays an essential role in the emergence of these peaks in the velocity distribution. We also find that the position of the peak at Vx(≠0) moves with the variation in the strength D of the random Brownian force, which also changes depending on physical parameters such as the kinematic viscosity, boundary velocity, and diameter of the plant cells.

Long-term holographic phase-contrast time lapse reveals cytoplasmic circulation in dehydrating plant cells.

The intracellular dynamics of onion epidermal cells during the dehydration process is observed by holographic microscopy. Both the nucleus and cytoplasm are accurately revealed by quantitative phase imaging while dehydration takes place. Indeed, we notice that the contrast of phase images increases with the decrease in cellular water content. We foresee that such a dehydrating process can be effective for improving phase contrast, thus permitting better imaging of plant cells with the scope of learning more about cellular dynamics and related phenomena. Exploiting this concept, we observe intracellular cytoplasmic circulation and transport of biological material.

Budding and Division of Giant Vesicles Linked to Phospholipid Production

The self-reproduction of supramolecular assemblies based on the synthesis and self-assembly of building blocks is a critical step towards the construction of chemical systems with autonomous, adaptive, and propagation properties. In this report, we demonstrate that giant vesicles can grow and produce daughter vesicles by synthesizing and incorporating phospholipids in situ from ad-hoc precursors. Our model involves acyl chain elongation via copper(I)-catalyzed azide-alkyne [3 + 2] cycloaddition reaction and the ensuing production of synthetic phospholipids to induce budding and division. In addition, the growth and budding of giant vesicles were compatible with the encapsulation and transfer of macromolecules as large as lambda phage DNA to the buds. This chemical system provides a useful model towards the implementation of cell-like compartments capable of propagation and transport of biological materials.

Determination of salmeterol in dried blood spot using an ionic liquid based dispersive liquid–liquid microextraction coupled with HPLC

A novel analytical method based on the use of a modified dispersive liquid–liquid microextraction (DLLME) technique by ionic liquids has been developed for the first time. This method was applied for the determination of salmeterol in dried blood spot samples from asthmatic patients followed by HPLC system equipped with fluorescence detector. The main novelty of the present work deals with the analysis of salmeterol in dried blood spot with significant advantages with regard to invasive sampling, volume of blood used (<20μL), storage and transport of biological materials and requirements for special biohazard arrangements. The effects of significant factors in microextraction procedure including extracting and disperser solvents volume, sample pH and salt contents were investigated. Under optimized conditions, the mean recoveries were higher than 90.0% with linear responses about 1.00–500ngmL−1 concentration range. The limit of detection (LOD) was 0.30ngmL−1 in S/N of 3. Intra-day (n=6) and inter-day (n=3) assay precision showed relative standard deviation lower than 6.0 and 8.5% for studied drug, respectively. The developed microextraction procedure was simpler and faster than conventional extraction techniques and was omitted hazard organic solvents. Finally, the proposed method is suitable for the analysis of salmeterol in dried blood spots from asthmatic patients for therapeutic drug monitoring purpose.

Does the time between collecting and processing umbilical cord blood samples affect the quality of the sample?

To assess the association between the time from umbilical cord blood collection until processing and the quality of the sample. Umbilical cord blood samples collected during the third stage of labor were placed in temperature-controlled boxes for the transport of biological material and sent to an umbilical cord blood bank, where the number of nucleated cells, viable cells and CD34+ cells were counted, and samples were additionally tested for contamination at the following time intervals: up to 24 hours, up to 48 hours and up to 72 hours following sampling. Data were analyzed using the multivariate analysis of variance (MANOVA) and compared using McNemar's χ2 test. Significance was defined at p < 0.05. Means and medians of the number of nucleated cells, viable cells and CD34+ cells decreased significantly (p < 0.0001) as a function of the increased time between sampling and analysis, the difference between 24 and 48 hours being less than the difference between 24 and 72 hours. A linear correlation was found between the mean number of viable cells and CD34+ cells at the three moments of analysis. Contamination testing was negative in all samples. The increase in time interval from sampling until analysis negatively affected the number of nucleated cells, viable cells and CD34+ cells but was not associated with specimen contamination. A linear correlation was found between decrease in the number of viable cells and CD34+ cells.

Mass transport induced by internal Kelvin waves beneath shore‐fast ice

A one‐layer reduced‐gravity model is used to investigate the wave‐induced mass flux in internal Kelvin waves along a straight coast beneath shore‐fast ice. The waves are generated by barotropic tidal pumping at narrow sounds, and the ice lid introduces a no‐slip condition for the horizontal wave motion. The mean Lagrangian fluxes to second order in wave steepness are obtained by integrating the equations of momentum and mass between the material interface and the surface. The mean flow is forced by the conventional radiation stress for internal wave motion, the mean pressure gradient due to the sloping surface, and the frictional drag at the boundaries. The equations that govern the mean fluxes are expressed in terms of mean Eulerian variables, while the wave forcing terms are given by the horizontal divergence of the Stokes flux. Analytical results show that the effect of friction induces a mean Eulerian flux along the coast that is comparable to the Stokes flux. In addition, the horizontal divergence of the total mean flux along the coast induces a small mass flux in the cross‐shore direction. This flux changes the mean thickness of the upper layer outside the trapping region and may facilitate geostrophically balanced boundary currents in enclosed basins. This is indeed demonstrated by numerical solutions of the flux equations for confined areas larger than the trapping region. Application of the theory to Arctic waters is discussed, with emphasis on the transport of biological material and pollutants in nearshore regions.

Rapid Whole Genome Amplification of DNA from Felids: Applications for Conservation Genetics

A major hindrance to conservation genetic studies of felids is the acquisition of DNA samples required for examining natural populations. In many cases research is complicated further by restrictions associated with the transport of biological materials from legally collected specimens. In this paper we assessed a method of rapidly amplifying whole genomes, both nuclear and mitochondrial, with the use of a strand displacement reaction (SDR) and the Phi29 DNA polymerase enzyme. We evaluated the SDR product with downstream amplification of microsatellite loci for genetic analyses of felids. The amplicon was of high molecular weight and provided a template equivalent to original DNA for polymerase chain reaction amplification of 10 microsatellites when properly stored samples were used. Genotypes of 6 felid species derived from genome amplifications scored identical to the original DNA, and we observed only 1 allelic dropout event among 67 heterozygotes. The Phi29 enzyme was able to amplify the genomes in samples up to 19 years old and those with degraded DNA. We extracted DNA and SDR amplified the genomes of 48 individuals of 5 felid species in Thailand in <3 days. We confirmed the SDR amplification of target DNA with 1 microsatellite for 47 of 48 samples (5 species).