Using Fe3O4-graphene oxide-modified chitosan with melamine magnetic nanocomposite in the removal and magnetic dispersive solid-phase microextraction of Cr (VI) ion in aquatic samples

An eco-friendly magnetic nanoparticle (MNPs)-based stir rod-assisted dispersive solid-phase extraction (SRMDSPE) method was proposed for the removal and extraction of Cr (VI) preceding its spectrophotometric determination. The magnetic melamine‐functionalized chitosan-modified graphene oxide (MCMGO) nanocomposites were synthesized as a biocompatible, effective adsorbent with admirable adsorption capacity, great magnetic property and excellent dispersion ability for the adsorption of the Cr (VI) ion. The prepared adsorbent was characterized by XRD, FTIR, TGA, VSM, EDX, and SEM. Different parameters affecting removal and microextraction efficiencies such as sample volume, pH, interferences, volume and type of eluent, and adsorbent dosage were investigated and optimized. The result of isotherm shows that Cr (VI) adsorption followed the Freundlich model. Thermodynamic parameters (i.e., change in the free energy (ΔG 0), the enthalpy (ΔH 0), and the entropy (ΔS 0)) were also evaluated. The overall adsorption process was endothermic and spontaneous. The sorbent elution with ability and reusability was used in dispersive solid-phase extraction. Under optimal conditions, the extraction efficiency was 78.0%, and the enrichment factor was 31.19. The SRMDSPE was successfully quantified in the 0.05–0.5 mg L−1 (R 2 = 0.9993) with a detection limit of 0.015 mg L−1. The proposed method was applied to leather wastewater, Tabriz, and some surface waters. The percentage of recoveries for spiked real samples were in the range of 91–101%, and the percentage of relative standard deviations were 2–6%

In vitro induction effect of 1,25(OH)2D3 on differentiation of hair follicle stem cell into keratinocyte

Background: Stem cells are characterized by self-renewal and differentiation capabilities. The bulge hair follicle stem cells (HFSCs) are able to convert to epithelial components. The active metabolite of vitamin D, 1,25(OH)2D3, plays important roles in this differentiation process. In the present study has found that 1,25(OH)2D3 induces the HFSCs differentiation into keratinocyte. Methods: HFSCs are isolated from rat whiskers and cultivated in DMEM medium. To isolate bulge stem cell population, flow cytometry and immunocytochemistry using K15, CD34 and nestin biomarkers were performed. In order to accelerate the HFSCs differentiation into eratinocyte, HFSCs were treated with 10−12 M, 1,25(OH)2D3 every 48 h for a week. Results: Immunocytochemistry results showed that bulge stem cells are nestin and CD34 positive but K15 negative before differentiation. Subsequently flow cytometry results, showed that the expression of nestin, CD34 and K15 were 70.96%, 93.03% and 6.88% respectively. After differentiation, the immunocytochemical and flow cytometry results indicated that differentiated cells have positive reaction to K15 with 68.94% expression level. Conclusion: It was concluded that 10−12 M, 1,25(OH)2D3 could induce the HFSCs differentiation into keratinocytes

The role of biodegradable engineered random polycaprolactone nanofiber scaffolds seeded with nestin-positive hair follicle stem cells for tissue engineering

Background: Tissue engineering is a new approach to reconstruction and/or regeneration of lost or damaged tissue. The purpose of this study was to fabricate the polycaprolactone (PCL) random nanofiber scaffold as well as evaluation of the cell viability, adhesion, and proliferation of rat nestin-positive hair follicle stem cells (HFSCs) in the graft material using electrospun PCL nanofiber scaffold in regeneration medicine. Materials and Methods: The bulge HFSCs was isolated from rat whiskers and cultivated in Dulbecco's modified Eagle's medium/F12. To evaluate the biological nature of the bulge stem cells, flow cytometry using nestin, CD34 and K15 antibodies was performed. Electrospinning was used for the production of PCL nanofiber scaffolds. Furthermore, scanning electron microscopy (SEM) for HFSCs attachment, infiltration, and morphology, 3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay for cell viability and cytotoxicity, tensile strength of the scaffolds mesh, and histology analysis were used. Results: Flow cytometry showed that HFSCs were nestin and CD34 positive but K15 negative. The results of the MTT assay showed cell viability and cell proliferation of the HFSCs on PCL nanofiber scaffolds. SEM microscopy photographs indicated that HFSCs are attached and spread on PCL nanofiber scaffolds. Furthermore, tensile strength of the scaffolds mesh was measured. Conclusion: The results of this study revealed that modified PCL nanofiber scaffolds are suitable for HFSCs seeding, attachment, and proliferation. Furthermore, HFSCs are attached and proliferated on PCL nanofiber scaffolds

Spectroscopic analysis of bosentan in biological samples after a liquid-liquid microextraction

Introduction: Microextraction processes with UV-Vis measurement have been developed and validated for analysis of bosentan in biological samples. Methods: In this work, liquid–liquid microextraction procedures (DLLME & USAEME) were employed for cleanup, pre-concentration, and determination of bosentan in biological samples by UV-Vis spectroscopy at 270 nm. The method was validated and applied to the determination of bosentan in spiked serum, exhaled breath condensate and urine samples. Results: Various experimental factors including type of extraction and dispersive solvents and their volumes, pH, sonication time and centrifuging time were investigated. Under the optimum conditions, the method was linear in the range of 1.0–5.0 μg.mL−1, with coefficient of determination (R2) of > 0.998. The limit of detection (LOD) was 0.07 mg.L−1. Recovery of the target analyte in biological samples was 106.2%. The method could be easily applied for higher concentration of bosentan and needs more improvement for application in the pharmacokinetic investigations where more sensitive methods are required. Conclusion: A simple, low cost, precise and accurate spectrophotometric analysis of bosentan in biological samples after liquid-liquid microextraction were developed and validated for routine analyses

The Validity and Reliability of the Persian Version of Test of ‎Mobile Phone Dependency (TMD) ‎

Objective:‎‏ ‏Despite the fact that ‎the mobile phone has become a ‎pervasive technology of our time, ‎little research has been done on ‎mobile dependency. A valid and ‎reliable assessment instrument ‎corresponding to the Persian ‎culture is essential. This study ‎aimed to describe the ‎construction and validation of the ‎Persian version of TMD (Test of ‎Mobile phone Dependency) to ‎assess the addictive use of ‎mobile phone.‎ Methods: This was a cross-‎sectional study, for which data ‎were collected from 350 students ‎who were studying at Tehran ‎universities. Sampling method ‎was quota sampling. The ‎participants anonymously ‎completed the demographic ‎questionnaire, and CPDQ as a ‎valid questionnaire and gold ‎standard. Finally, clinical ‎interview [based on DSM-IV-TR] ‎was performed. To analyze the ‎data, concurrent validity, factor ‎analysis, internal consistency ‎‎(Cronbachα), split half; test-retest ‎and ROC Curve by SPSS18 ‎Software were used.‎ Results: As a result of the ‎reliability analysis and factor ‎analysis by principal component ‎and Varimax rotation, three ‎factors (“salient”, “preoccupation” ‎and “Spend a lot of time and ‎money”) for both male and ‎female participants were ‎extracted. Internal consistency ‎‎(Cronbach's alpha) of the CPDQ ‎was .92 (Cronbach alpha of the ‎factors is .88, .82, and .84, ‎respectively). The test-retest ‎correlation of the TMD was ‎‎.56.The best cut off point for this ‎questionnaire (TMD) is 38.‎ Conclusion: The TMD proved to ‎have an acceptable internal ‎consistency with adequate factor ‎models to assess the extent of ‎problems caused by the "misuse" ‎of the mobile phone in the ‎Iranian society. Therefore, it can ‎be concluded that the Persian ‎version of the test was reliable ‎and valid; however, further ‎analysis is needed.