Internal Standard an Important Analyte Use in Drug Analysis by Liquid Chromatography Mass Spectrometry- An Article

Internal standard is an external compound which is mixed with targeted analytical solution and matrix as a constant concentration and use for preparing calibration standard curve by using ratio of analyte area and internal standard area with analyte concentration and internal standard concentration. This calibration curve used for quantification of unknown concentration of anlayte of interest. This article provide necessary information about internal standard like its selection procedure, characterization, types and response factor , to all analyst who are connected with drug analysis. This article is more important and I think first article which focuses a clear idea about internal standard use in drug analysis.

О вакансионной природе высокотемпературного фона внутреннего трения в твердых телах

High-temperature internal friction in an amorphous CuTi alloy is investigated. Exponential regions with different activation energies are observed on the dependence of internal friction on temperature on both sides of the glass transition temperature. An exponential increase in the background of internal friction with temperature in both sites is associated with the migration of vacancy-like defects in the amorphous structure under the influence of mechanical stresses, while frozen defects of constant concentration migrate to the glass transition temperature. After the transition to a state of thermodynamic equilibrium , the concentration the number of migrating defects increases exponentially. Based on the experimental results of measuring the high-temperature background, estimates of the activation energy of migration and the formation of vacancies of similar defects in the amorphous structure of the alloy under study are made.

The Effect of the Liposomal Encapsulated Saffron Extract on the Physicochemical Properties of a Functional Ricotta Cheese

In this study, the encapsulation of saffron extract (SE) was examined at four various concentrations of soy lecithin (0.5%–4% w/v) and constant concentration of SE (0.25% w/v). Particle size and zeta potential of liposomes were in the range of 155.9–208.1 nm and −34.6–43.4 mV, respectively. Encapsulation efficiency was in the range of 50.73%–67.02%, with the stability of nanoliposomes in all treatments being >90%. Encapsulated SE (2% lecithin) was added to ricotta cheese at different concentrations (0%, 0.125%, 1%, and 2% w/v), and physicochemical and textural properties of the cheese were examined. Lecithin concentration significantly (p ≤ 0.05) affected the particle size, zeta potential, stability, and encapsulation efficiency of the manufactured liposomes. In terms of chemical composition and color of the functional cheese, the highest difference was observed between the control cheese and the cheese enriched with 2% liposomal encapsulated SE. Hardness and chewiness increased significantly (p ≤ 0.05) in the cheeses containing encapsulated SE compared to the control cheese. However, there was no significant difference in the case of adhesiveness, cohesiveness, and gumminess among different cheeses. Overall, based on the findings of this research, liposomal encapsulation was an efficient method for the delivery of SE in ricotta cheese as a novel functional food.

Power Law Kernel Analysis of MHD Maxwell Fluid with Ramped Boundary Conditions: Transport Phenomena Solutions Based on Special Functions

In this paper, a new approach to find exact solutions is carried out for a generalized unsteady magnetohydrodynamic transport of a rate-type fluid near an unbounded upright plate, which is analyzed for ramped-wall temperature and velocity with constant concentration. The vertical plate is suspended in a porous medium and encounters the effects of radiation. An innovative definition of the time-fractional operator in power-law-kernel form is implemented to hypothesize the constitutive mass, energy, and momentum equations. The Laplace integral transformation technique is applied on a dimensionless form of governing partial differential equations by introducing some non-dimensional suitable parameters to establish the exact expressions in terms of special functions for ramped velocity, temperature, and constant-concentration fields. In order to validate the problem, the absence of the mass Grashof parameter led to the investigated solutions obtaining good agreement in existing literature. Additionally, several system parameters were used, such as as magnetic value M, Prandtl value Pr, Maxwell parameter λ, dimensionless time τ, Schmidt number “Sc”, fractional parameter α, andMass and Thermal Grashof numbers Gm and Gr, respectively, to examine their impacts on velocity, wall temperature, and constant concentration. Results are also discussed in detail and demonstrated graphically via Mathcad-15 software. A comprehensive comparative study between fractional and non-fractional models describes that the fractional model elucidate the memory effects more efficiently.

Special functions-based solutions of unsteady convective flow of a MHD Maxwell fluid for ramped wall temperature and velocity with concentration

In this paper a new approach is taken to find the exact solutions for generalized unsteady magnetohydrodynamic transport of a rate-type fluid near an unbounded upright plate and is analyzed for ramped wall temperature and velocity with constant concentration. The vertical plate is suspended in a porous medium and encounters radiation effects. Solutions based on special functions are obtained using an integral transform for an unsteady MHD Maxwell fluid in the presence of ramped velocity, temperature and constant concentration. The relations for Nusselt number and skin-friction coefficient are efficiently computed to precisely estimate the rate of heat transfer at the boundary and the shear stress. Results are also discussed in detail and demonstrated graphically using software to comprehensively analyze the dynamics of the proposed problem, and the physical impact of several system parameters, such as magnetic field M, Prandtl number Pr, the relaxation time λ, dimensionless time τ, Schmidt number Sc, Mass and Thermal Grashof numbers Gm and Gr, respectively, is studied. Furthermore, solutions for some recently published work are compared with the current study that endorses the authenticity of our derived results and proves that those investigations are limiting or special cases of the current problem.

Simulation of cancer treatment using the MATLAB SimBiology application

The paper presents the implementation of the mathematical model of cancer taking into account interference competition and the model of continuous treatment with a constant concentration of the drug in the patient's blood. The implementation was carried out using the MATLAB SimBiology application package. The principle of implementation of different stages of the course of the disease within the framework of one model is described. On the basis of the constructed models and SimBiology tools, a modification was carried out that implements the discrete administration of doses of the drug in courses and takes into account its dynamics in the body, taking into account the assumption that the drug is consumed only to suppress cancerous cells.

Effect of 1-naphthylacetic and indol-3-acetics acid on the intensity of callusogenesis and organogenesis of Linum usitatissimum L. in vitro

Aim. Investigate the effect of auxins of exogenous origin in nutrient medium in vitro on the germination and organogenesis intensity in Linum usitatissimum L. convar. elongatum (‘Hlinum’ variety) at the constant concentration of 6-benzylaminopurine (BAP). Methods. Hypocotyl segments were cultured on Murashige and Skoog nutrient medium supplemented with sucrose (30 g/l) and phytohormones at various concentrations. Other conditions: photoperiod 16 hours, relative humidity 60–80%, air temperature 22–24°C. Results. Common flax has a great capacity to form callus and shoots under the effect of the following factors: 1) only auxins, 2) only cytokines, 3) combinations of auxins and cytokines. Somatic embryogenesis is also possible on a nonhormonal nutrient medium. Conclusions. For somatic embryogenesis in vitro, the optimal concentrations of BAP can be expressed as 1.0 ≤ BAP ≤ 1.75, the optimal concentrations of BAP for the medium supplemented with 1-naphthylacetic (NAA, 0.05 mg/l) 0.5 ≤ BAP ≤ 2.0, the optimal concentration of NAA for the medium supplemented with BAP (1.0 mg/l) 0.025 ≤ NAA ≤ 0.150, and the optimal concentrations of indol-3-acetics acid (IAA) for the medium supplemented with BAP (1.0 mg/l) 0.05 ≤ IAA ≤ 0.50. Keywords: Linum usitatissimum L., in vitro, phytohormones, callus, organogenesis.

Soil moisture migration model based on Flux-concentration relation under steady rainfall

Moisture content distribution in soil is of great importance for understanding rainfall-induced slope failure and roadbed settlement. This study aims to develop a moisture migration model that improves the quantification of moisture content at an arbitrary point of the soil at any time for the whole process of infiltration under steady rainfall. The model was derived from the Richards' equation using the Flux-concentration relation, which was validated by numerical solutions calculated by Hydrus-1D software to evaluate the performance of the model. Results showed good accuracy and high adaptability for the moisture migration simulation of a wide range of soil types, and is applicable for short-duration and long-duration steady rainfall. Moreover, it can also reflect the stratification phenomenon for soil profile wetting by infiltration. Our analysis indicates that the flux and surface volumetric moisture content together can bound the boundary conditions of rainfall infiltration, which presents a shift from constant-flux to constant-concentration during a long-duration steady rainfall. The migration rate of the wetting front in the later stage of infiltration positively correlates with rainfall intensity under the constant-flux condition, while it finally stabilizes at Ks/(θs − θi) under the constant-concentration condition (i.e., Ks-saturated hydraulic conductivity, θs-saturated volumetric moisture content, θi-initial volumetric moisture content). HIGHLIGHT Moisture migration model was derived to improve the quantification of moisture content at an arbitrary point of the soil at any time for the whole process of infiltration under steady rainfall, which shows good accuracy and high adaptability for the moisture migration simulation of a wide range of soil types, and is applicable for short-duration and long-duration steady rainfall.

Influence of the NaIO4 Concentration on the Gelation and the Adhesive Strength of Pyrocatechol/Pyrogallol Containing Gelatin Hydrogels

The presence of catechol groups in hydrogels, either grafted to the constituting polymers or added in the gel formulation allow to increase the adhesion strength of such hydrogels. In this investigation, we add pyrocatechol (1,2-benzenediol) and pyrogallol (1,2,3-benzenetriol) in gelatin solution to form hydrogels using sodium periodate as an oxidant with the aim to induce interactions between pyrocatechol/pyrogallol and the gelatin chains. The gelation kinetics of the hydrogels as well as their adhesion strength and toughness are evaluated as a function of the concentration in NaIO4 for a constant concentration-10 mM-in pyrocatechol/pyrogallol. It came out that the addition of pyrogallol to gelatin (10% w/v) did not improve the adhesion strength on stainless steel when compared to a pristine gelatin gel. As an interesting finding, the addition of pyrocatechol to gelatin allowed for a major improvement of the adhesive strength between two stainless steel plates and allowed to stabilize the gel up to 50°C. However, the pyrogallol modified gelatin gels displayed no thermal stabilization compared to pristine gelatin. The major differences between pyrocatechol and pyrogallol modified gels are explained on the basis of the electrophilicity of the oxidized polyphenols. In addition, the self-healing behavior of the gelatin based gels was investigated as a function of their composition.

Biofabrication of chitosan/chitosan nanoparticles/polycaprolactone transparent membrane for corneal endothelial tissue engineering

We aimed to construct a biodegradable transparent scaffold for culturing corneal endothelial cells by incorporating chitosan nanoparticles (CSNPs) into chitosan/polycaprolactone (PCL) membranes. Various ratios of CSNP/PCL were prepared in the presence of constant concentration of chitosan and the films were constructed by solvent casting method. Scaffold properties including transparency, surface wettability, FTIR, and biocompatibility were examined. SEM imaging, H&E staining, and cell count were performed to investigate the HCECs adhesion. The phenotypic maintenance of the cells during culture was investigated by flow cytometry. Transparency and surface wettability improved by increasing the CSNP/PCL ratio. The CSNP/PCL 50/25, which has the lowest WCA, showed comparable transparency with human acellular corneal stroma. The scaffold was not cytotoxic and promoted the HCECs proliferation as evaluated by MTT assay. Cell counting, flow cytometry, SEM, and H&E results showed appropriate attachment of HCECs to the scaffold which formed a compact monolayer. The developed scaffold seems to be suitable for use in corneal endothelial regeneration in terms of transparency and biocompatibility.