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Aerodux 185 liquid phenol-resorcinol resin adhesive mixed with a powder hardener provides a cold-setting weatherproof adhesive especially suited to the manufacture of exterior high hazard structural components as defined in BS 5268 : Part 2. The adhesives are also suited to the production of heat resistant composite structures, e.g., fire-resisting doors.
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According to court documents and evidence presented during trial, at the time of his arrest last year, Aldawsari had been researching online how to construct an IED using several chemicals as ingredients. He had also acquired or taken a substantial step toward acquiring most of the ingredients and equipment necessary to construct an IED and he had conducted online research of several potential U.S. targets. In addition, he had allegedly described his desire for violent jihad and martyrdom in blog postings and a personal journal.
The government presented evidence that on Feb. 1, 2011, a chemical supplier reported to the FBI a suspicious attempted purchase of concentrated phenol by a man identifying himself as Khalid Aldawsari. Phenol is a toxic chemical with legitimate uses, but can also be used to make the explosive trinitrophenol, also known as T.N.P., or picric acid. Ingredients typically used with phenol to make picric acid, or T.N.P., are concentrated sulfuric and nitric acids.
tear test used to evaluate tear production in evaluating patients with dry eyes - tests the assessment of lacrimal insufficiency - cotton thread treated with phenol red, which changes colour from yellow to red on contact with tears - 50 pouches with 2 strips - CE mark
tear test used to evaluate tear production in evaluating patients with dry eyes - tests the assessment of lacrimal insufficiency - cotton thread treated with phenol red, which changes colour from yellow to red on contact with tears - it is less invasive than the Schirmer test - 50 small bags containing 2 threads - sterile - CE marked *
Abstract: Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-HN hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-HN hydrogen bonds. In (III), strong intermolecular O-HN hydrogen bonds and weak intramolecular C-HO hydrogen bonds lead to the formation of an infinite chain of molecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions.
As phenol possesses a threat to human health, there is a great demand to search for fast and efficient methods for it to be discharged. In this study, a novel biomaterial was prepared by the immobilization of bacteria on a cationic straw carrier, and the remediation ability of the biomaterial on phenol-containing wastewater was investigated. The free bacteria could degrade 1,000 mg/L phenol within 240 h, while the prepared biomaterial was 192 h, shortening by 48 h that of free bacteria. In addition, the degradation tolerance of biomaterial increased from 1,000 mg/L to 1,200 mg/L than the free bacteria, within 216 h, which shortened by 24 h the degradation time of 1,000 mg/L phenol by free bacteria (240 h). Further, under different pH conditions, the degradation efficiency of phenol by prepared biomaterial was much higher than that of free bacteria. Especially for the lower pH 5, the degradation efficiency of biomaterial was nearly twice that of the free bacteria. This investigation demonstrates that this biomaterial has great potential in the field of remediation of organic pollution.
Phenol is an important industrial material, but its high biological toxicity results in a serious environmental and health threat for the whole world (Stoilova et al. 2006; Nikl et al. 2019). As the extensive applications and pollution in the fields of oil refining, coking, and papermaking, and excellent water solubility of phenol, solutions for phenol-containing wastewater and soil pollution must be raised (Saha et al.1999; Michałowicz & Duda 2007; Naguib et al. 2019). At present, physical adsorption, biodegradation, chemical catalysis and solvent extraction are the main treatment for phenol-containing wastewater (Yang et al. 2018; Liu et al. 2019). Because of the advantages of complete degradation and no secondary pollution, biodegradation is widely regarded as a practical, economical and promising method (Azadi & Shojaei 2020; Lee et al. 2020; Nogina et al. 2020). Various kinds of microorganisms with the ability of degradation of phenol have been favored, such as Pseudomonas, Acinetobacter, yeasts, and activated sludge with a wide variety of microorganisms (Filipowicz et al. 2020; Lin & Cheng 2020; Liu et al. 2020; He et al. 2021). In general, as the concentration of hazardous pollutants increases, the ability of natural microorganisms for degradation is decreased. Except for high concentrations of phenol, the inevitable factors in wastewater such as adverse pH, temperature, and metal ions, which poison the growth of microorganisms, have significant effect on the removal of phenol (Nouri et al. 2020; Rongsayamanont et al. 2020; Barik et al. 2021). Thus, the development of methods to rapidly and efficiently remove phenol in a high concentration that can also maintain or improve the survival and degradation efficiency of bacteria in a harsh pH or temperature condition, is very necessary.
Herein, a novel composite material of bacteria immobilized on cationic straw through electrostatic interaction between negative Pseudomonas aeruginosa and positive straw grafted by amino groups, for the bioremediation of phenol, has been prepared. This strategy possesses some advantages. Cationic straw was firstly applied to fix bacteria to degrade phenol. Comparing with the free bacteria, the immobilized bacteria can effectively shorten the degradation time, increase the degradation rate, and enhance the degradation concentration of phenol. In addition, under some harsh environments, especially low pH, fixed bacteria can more effectively degrade phenol. Further, microorganisms with different abilities can be employed to degrade various kinds of pollution. It should be noted that using modified biomass materials to immobilize microorganisms is an effective, green and promising method for the treatment of polluted wastewater, providing the unity of social benefit, economic benefit and environmental benefit.
The acclimation process of the strain was carried out in MSM by gradually increasing the concentration of phenol 100 mg/L per three days and decreasing the concentration of glucose in MSM medium (100 mg/L) per three days, until the concentration of glucose reduced to 0 mg/L and phenol increased to 1,000 mg/L. The acclimation was accomplished as inoculation 10% (v/v) at 37 C and 180 rpm. Then, the strain was used to degrade 1,000 mg/L phenol, as the sole carbon source with several circulations, to obtain a stable bacteria. Finally, the bacteria were activated in MSM medium for phenol degradation, inoculated for 10% (v/v) and cultured at 37 C and 160 rpm. The concentration of phenol was detected by 4-aminoantipyrine method (Baird et al. 2017).
The fermentation broth with the strain was centrifuged at 5,000 rpm for 20 min, then the supernatant was discarded, followed by washing with sterile water. After that, the strain was re-suspended with sterile water, whose optical density was 1.0 0.13. The linear relationship between the number of bacteria and the optical density can be obtained by the spread plate method. After the sterilization of cationic straw, the straw and bacterial suspension were mixed at a solid-liquid ratio of 1:100 at 30 C and 120 rpm for 6 h. The amount of immobilized bacteria was determined by the above linear curve (Yue et al. 2013). The number of immobilized bacteria on straw was 1.3 109 CFU/g. After filtration, the immobilized material was mixed with 5% (w/w) trehalose, then freeze dried to constant weight and stored at 4 C (Xu et al. 2010a, 2010b). For phenol degradation, the immobilized material was added into MSM medium where phenol acts as the sole carbon source at a solid-liquid ratio of 1:100. In addition, degradation with phenol concentrations of 1,000 and 1,200 mg/L were carried out, respectively.
After sterilization, pH of the culture medium was adjusted to 5, 6, 7, 8 and 9 under aseptic conditions, respectively. Then, strains and immobilized material were added in the MSM medium, respectively, to degrade phenol at 37 C for 5 days. Then, the culture medium was centrifuged, and the supernatant was used to determine the concentration of phenol.
Among the various methods for phenol treatment, microbial degradation is welcome due to its advantages of a high removal rate, more thorough degradation, and no secondary pollution to the environment. Pseudomonas putida is a kind of microorganism for effective degradation of phenol, which can grow on the culture medium where phenol acts as the sole carbon source (Umashankar et al. 2018). As the initial strain we used could not survive on the sole carbon source of phenol, acclimation of the strain was raised by gradually increasing the concentration of phenol and decreasing the concentration of glucose medium. In order to study the degradation ability of the acclimated strain, phenol degradation at different initial concentrations from 500 to 1,250 mg/L was investigated, as shown in Figure 3. The highest degradation concentration of the strain is 1,000 mg/L. With the increase of the concentration, the delay period and the degradation time of phenol gradually increase. At the concentration of 1,000 mg/L, the bacteria could totally remove phenol within 240 h, while for 500 and 750 mg/L phenol, 144 h is used. With the rising phenol concentration, both the degree of poisoning of bacteria and the inhibition of enzymes are increased. Thus, the bacteria need more time to adapt to a high concentration of phenol and improve the number of bacteria, resulting in a slower degradation rate. In addition, when the phenol concentration exceeds 1,000 mg/L, the bacteria are beyond sufferance and death occurs. 041b061a72