Cosmetic Components Causing Contact Urticaria Syndrome: An Update
Ana M. Giménez-Arnau, Howard I. Maibach in Contact Urticaria Syndrome, 2014
Persulfate salts are widely used in hair-bleaching formulas: they have a strong oxidizing action that accelerates the bleaching process and also makes the hair more receptive to the dyes, especially the light shades.[4] Nowadays, potassium persulfate is more frequently used than ammonium salt, because the latter has an unpleasant odor.[15] Ammonium persulfate is a low-molecular-weight chemical and is a known cause of urticaria, contact dermatitis, rhinitis, and asthma, the latter mainly by inhalation in an occupational context.[1] Asthmatics seem to be particularly susceptible to develop such reactions.[16] Some studies could demonstrate specific binding of IgE to persulfates by two methods, immunospot and radioallergosorbent test, hence the mechanism of immediate hypersensitivity to persulfates seems to be IgE-mediated at least in some patients.[4] Yawalker et al. provided evidence that T lymphocytes specific for low molecular compounds such as persulfates may be directly involved in mediating inflammatory processes in the airways, rather than only acting through induction of IgE synthesis in persulfate-triggered occupational asthma.[17]
Mathematical Modeling and Analysis of Soft Tissue Viscoelasticity and Dielectric Relaxation
A. Bakiya, K. Kamalanand, R. L. J. De Britto in Mechano-Electric Correlations in the Human Physiological System, 2021
Tissue-mimicking materials are frequently utilized as phantoms or physical models to study, understand and simulate the properties of human and animal soft tissues (Madsen et al., 1982). In medical research, phantom materials are utilized as a substitute for soft tissues in cases where in-vivo tissues are unavailable. Tissue-mimicking phantoms can be synthesized to mimic the material properties as well as the geometry of anatomical features, such as blood vessels and internal organs (Surry et al., 2004). The tissue-mimicking materials are crucial in clinical studies for the development and validation of new medical devices as well as for the calibration of diagnostic and surgical instruments (Takegami et al., 2004; Erkamp et al., 2004). Various tissue-mimicking phantoms such as agar, epoxies, polymers, urethanes and other natural as well as artificial materials have been utilized to simulate the material properties and the geometry of soft tissues. Some patented materials, such as Zerdine which has properties similar to human liver tissue, exist as well (Rowan and Pedersen, 2006). Tissue-mimicking polyacrylamide gels were reported to be well suited for both bioelectrical and biomechanical analysis as these properties are tunable in the physiological range (Kao et al., 2008; Krishnamurthy et al., 2009). In this section, the preparation of two different tissue-mimicking phantom materials is discussed. Agar phantoms: Agar phantoms can be prepared in any shape, size and geometry by heating a solution made of Agar Agar powder in distilled water to a temperature of 160°C until the solution becomes transparent and viscous. The solution is then cooled to obtain the phantom material (Zell et al., 2007). Various tissues can be modeled by varying the concentration of Agar powder in distilled water.Polyacrylamide phantoms: Polyacrylamide phantoms are tissue-mimicking materials which are synthesized by the chemical polymerization reactions. These phantoms are synthesized by the co-polymerization of the monomer acrylamide and bis-acrylamide. A 40% polyacrylamide phantom requires a mixture of 38 g monomer acrylamide and 2 g bis-acrylamide dissolved in 100 mL deionized water. Ammonium persulfate is used as an initiator to initiate the reaction between the acrylamide and bis-acrylamide. TEMED (N, N, N’, N’-tetramethylethylenediamine) is added as a catalyst for the polymerization reaction. Polyacrylamide gels can be synthesized to mimic the material properties such as the viscoelastic, dielectric and optical properties of several soft tissue types by varying the concentration of the monomer acrylamide (Kamalanand et al., 2010).
Embryonic growth retardation and altered expression of IGF-II is reciprocal induced by phytocompounds during early gestation in mice
Published in Growth Factors, 2022
Khamhee Wangsa, Krishnakshi Misra, Upasa Gowala, Indira Sarma, Purba Jyoti Saikia, Hirendra Nath Sarma
The protein samples of both treated and control from D4 to D8 has been separated by discontinuous single dimensional SDS-PAGE (following the method of Ausubel et al. 1992), using 5% stacking gel and 15% separating gel. The gels were prepared using acrylamide (Merck, Germany M.W.71.08) and bis-acrylamide (N,N′-methylene bisacrylamide, Merck, Germany, M.W. 154.17) in the ratio of 29:1. Tris buffer (PH 8.8 and 6.8) was prepared using 1.5M Tris (Himedia, M.W. 121.14). The polymerising agents used were Ammonium persulfate (Qualigens fine chemicals, M.W. 228.20) and TEMED (Ottochemi, M.W. 116.21). SDS (Calbiochem, M.W. 288.4) was used as the denaturing agent which also gave the net negative charge to the proteins such that the proteins run towards the anode end. Protein samples were extracted from 25mg of uterine tissue on each day of experiment of both control and CESD-treated mice in similar volume of extraction buffer. The protein samples of both control and CESD-treated females of each day of gestation was loaded in a final concentration of 50µg/20µl for separation in SDS–PAGE. . The electrophoretic separation was performed in the tetra cell electrophoretic apparatus (Bio-Rad, USA).
A tissue-mimicking prostate phantom for 980 nm laser interstitial thermal therapy
Published in International Journal of Hyperthermia, 2019
R. Geoghegan, A. Santamaria, A. Priester, L. Zhang, H. Wu, W. Grundfest, L. Marks, S. Natarajan
To reduce the coagulation temperature of BSA to 60 °C, a 0.2 M citrate buffer was added to ensure a Ph∼4.7. The buffer consists of citric acid anhydrous (Sigma-Aldrich, MI, C0759) and sodium citrate tribasic dihydrate (Sigma-Aldrich, MI, S4641). Further details on this method can be found in McDonald et al. [20]. To prevent bubbles from appearing in the phantom, the BSA was thoroughly degassed and added after all other ingredients were dissolved in water. Since the polymerization reaction is exothermic and could cause premature BSA coagulation, the solution was chilled (4–8 °C) before adding the initiator. Due to the reduced pH, the widely used combination of TEMED and ammonium persulfate could not be used to initiate polymerization. Instead, polymerization was initiated via a combination of L-ascorbic acid (Sigma-Aldrich, MI, A5960), iron (II) sulfate heptahydrate (Sigma-Aldrich, MI, F7002) and hydrogen peroxide (30% w/v, Sigma-Aldrich, MI, H1009) as previously used by McDonald et al. [20]. The solution was then immediately poured into 70 mm × 70 mm × 40 mm thin-walled (1 mm) prefabricated molds, sealed and refrigerated. Table 1 shows the recipe for a 1 L phantom without altering the optical properties by addition of Naphthol Green B, Intralipid or BSA. Throughout this paper, the increase in volume due to the addition of BSA and/or Intralipid addition was offset by a corresponding reduction in water volume; hence, the total volume remained constant.
Determination of some adsorption and kinetic parameters of α-amylase onto Cu+2-PHEMA beads embedded column
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Ömür Acet, Neşe Hayat Aksoy, Demet Erdönmez, Mehmet Odabaşı
Preparation of Cu+2-PHEMA beads embedded cryogel (Cu+2-BEC) column is as follows: Firstly, the monomer mixture was made by dissolving 6 mmol of 2-hydroxyethyl methacrylate (HEMA as monomer) and 1 mmol of N,N′-methylene-bis-acrylamide (MBAA as cross-linker) in 14 mL of deionized water. Obtained monomer solution was subjected to nitrogen atmosphere for nearly 5 min in order to remove soluble oxygen. The mixture was poured into three plastic syringes (5 mL, id. 0.8 cm) to get three columns. After adding 20 mg of Cu+2-PHEMA beads into each column solutions separately, columns were kept in an ice bath to reduce the temperature of solutions to about 0 °C. Then, ammonium persulfate (10%, 10 μL)/N,N,N´,N´ tetramethylene diamine (10 μL) as initiator/activator pair were added into the column mixtures to start the polymerization, and they were immediately placed in a refrigerator at −12 °C for 24 h. At the end, Cu+2-BEC column, obtained, was taken from the refrigerator, and thawed at 25 °C, and washed with deionized water. Cu+2-BEC columns were stored in a buffer with 0.02% sodium azide at 4 °C until use. Representation of Cu+2-BEC column for α-amylase is shown in Figure 1.
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