The occurrence of nine phthalic acid esters (PAEs) were determined in indoor dust samples collected from vehicle repair shops, waste processing workshops, and homes in Vietnam. Concentrations of ...total PAEs ranged from 585 to 153,000 (median 33,400 ng/g), which fall in the lower end of global range. The PAE levels in workplace dust (median 49,100; range 9210–153,000 ng/g) were significantly higher than those in house dust (median 23,700; range 585–83,700 ng/g), indicating waste processing activities as potential PAE sources. The most predominant compound was di-(2-ethyl)hexyl phthalate (DEHP), accounting for 62 ± 18% of total PAEs. Other major compounds were benzyl butyl phthalate (BzBP) (10 ± 12%), di-
n
-butyl phthalate (DnBP) (9.7 ± 7.7%), di-
n
-octyl phthalate (DnOP) (7.9 ± 8.1%), and diisobutyl phthalate (DiBP) (6.9 ± 5.0%). Proportions of BzBP and DnBP in some workplace dust samples were markedly greater than in common house dust, suggesting specific emission sources. Daily intake doses of selected PAEs (e.g., DnBP, DiBP, BzBP, and DEHP) through dust ingestion were much lower than reference doses, implying acceptable levels of risk.
Full text
Available for:
CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this work, the effects of controlled nanoparticles aggregations of barium titanate (BaTiO3) on the dielectric properties of epoxy nanocomposites are investigated in detail with respect to ...different experimental parameters like frequency, ceramic content and temperature. Dispersing silanized BaTiO3 nanopowder under ultrasonic and stir, nanocomposites of epoxy-amine matrix with different morphologies are obtained. The nanoparticles silane functionalization containing amine end groups effectively improve the compatibility of the nano-BaTiO3 and the epoxy matrix. Storage modulus, glass transition temperature, tensile and flexural properties of nanocomposites and dielectric properties are increased until 10% by weight of nano-BaTiO3 loading, well dispersed in the matrix. Above 10wt.% of nano-BaTiO3, scanning electronic microscopy and thermal analysis showed that agglomeration of nanoparticles occurs. Rheological and mechanical nanocomposites properties were evaluated and matrix occlusion behaviors were identified. In light of the specific behavior of the occluded polymer, the dielectric properties, especially dielectric loss are discussed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In the study, Fe was used as a dopant to enhance photocatalytic activity of TiO2. Then, the Fe-doped TiO2 was deposited on bentonite, which was pillared by Fe. The synthesized materials were ...characterized by SEM, XRD, UV-Vis, BET, and point of zero charge (pHPZC). Then, the synthesized materials were used for diazinon removal under both dark and visible light conditions to investigate adsorption and photocatalytic degradation abilities of the synthesized materials. The maximum diazinon adsorption capacity of the synthesized Fe-TiO2/Bent-Fe was 27.03 mg/g. The obtained results indicated that the Fe-TiO2/Bent-Fe exhibited high photocatalytic degradation activity for removal of diazinon even under visible light. The diazinon removal experiments were also conducted using different photocatalyst dosages, under different pH and light sources to figure the optimal conditions for removal processes. The obtained results indicated that optimal photocatalyst dosage and pH were 0.5 g/L and 4.5, respectively. Finally, the natural light generated from solar could be suitable used for diazinon removal by the synthesized Fe-TiO2/Bent-Fe.
Full text
Available for:
FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Houttuynia cordata Thunb. has long been widely used as a daily vegetable and traditional medicine. The flavonoid component of H. cordata has plenty of pharmacological effects, such as antibacterial, ...anti-inflammatory, and antioxidant. In this study, we applied the aqueous two-phase system (ATPS) combined with ultrasonic extraction for extracting H. cordata leaves.
We optimized the extraction process to improve the extraction efficiency of the two flavonoids, hyperin and quercitrin, by Surface Method Response - Central Composite Design (RSM-CCD). Next, we investigated the antibacterial ability of H. cordata ATPS extract from optimal conditions against two bacterial strains, Cutibacterium acnes and Staphylococcus epidermidis.
The results showed that using 10% (NH4)2SO4 and 35% ethanol for ATPS extraction resulted in the highest hyperin and quercitrin contents. From the RSM-CCD results, the optimal extraction conditions were determined to be ultrasonic extraction at 50 °C for 30 min, giving results consistent with the predicted model and obtaining hyperin and quercitrin contents at 1.5681 ± 0.0114 and 4.6225 ± 0.0327 mg/g, respectively.
Furthermore, ATPS extract has excellent antibacterial activity with a minimum inhibitory concentration (MIC) value of 250 μg/mL on both C. acnes and S. epidermidis. This MIC is significantly lower than the H. cordata ultrasound-assisted (UA) extract, with MICs of 1500.00 and 156.25 μg/mL on C. acnes and S. epidermidis, respectively. In addition, the results from the disk diffusion assay also showed that ATPS extraction has superior internal antibacterial activity with a zone of inhibition diameter at 250 μg/mL of 8.67 ± 1.15 and 5.00 ± 2.00 mm. Meanwhile, those of UA extract on C. acnes is 5.67 ± 1.53 mm (at 1500 μg/mL), and on S. epidermidis is 1.34 ± 0.58 mm (at 156.25 μg/mL).
To sum up, our research highlights the potential of H. cordata ATPS extracts as the starting material for topical preparations for effectively treating acne.
•Successfully utilized aqueous two-phase system (ATPS) with 10% (NH4)2SO4 and 35% ethanol to obtain specific flavonoids-rich extracts.•From the Response Surface Methodology results, the optimal conditions for ATPS extraction were ultrasonic extraction at 50 °C for 30 min, giving results consistent with the predicted model.•ATPS extracts exhibit potential antibacterial activity against Cutibacterium acnes and Staphylococcus epidermidis.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The surface modification of synthesized nano-BaTiO3 particles was carried out using γ-aminopropyl trimethoxy silane (γ-APS) in an ethanol/water solution. The modified particles were characterized by ...FTIR, TGA, surface charge analysis, and by dielectric constant measurement. The silane molecules were attached to the surface of BaTiO3 particles through SiOBaTiO3 bonds. The γ-APS grafted on BaTiO3 made the dielectric constant of the particles increase at frequencies ≥0.3 kHz in a wide range of temperature (25 °C–140 °C), due to the presence of NH2 groups. The dependence of the polarization vs. electrical field was measured in order to elucidate the dielectric behavior of the silane treated BaTiO3 in comparison to untreated BaTiO3. The nanocomposite based on epoxy resin containing BaTiO3 nanoparticles untreated and treated with γ-APS was also prepared and characterized. The results indicated that the γ-APS-modified BaTiO3 surfaces significantly enhanced the dielectric property of the nanocomposite.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Agilent’s innovative EMR-Lipid and Captiva EMRLipid sorbents efficiently replace the traditional QuEChERS d-SPE clean-up products in selective lipid removal from fatty matrices, thus improving ...instrumental analytical reproducibility, reliability, and long-term use. These products have dual functionality; a hydrophobic interaction between the sorbent with long aliphatic lipid chains of the matrices, which allows for complete lipid retention, and a size exclusion property that does not retain analytes, thus this maximizes, in principle, analyte recovery in any sample. As most of the analytes under study were polar or not highly nonpolar and had a relatively large size, the examination of small-sized nonpolar or less polar compounds is necessary to check for partial retention by the sorbents and if any, further precautions should be taken when using these sorbents. These queries are answered in our present communication concerning the analytes Trifluralin (logP: 5.27), Fipronil (logP: 4.0), and Clenbuterol (logP: 2.63).
The platinum-catalyzed hydroamination of ethylene with aniline is reported for the first time. Using PtBr2 as a catalyst precursor in n-Bu4PBr under 25 bar of ethylene pressure affords N-ethylaniline ...with 80 turnovers after 10 h at 150 °C. The reaction simultaneously produces 2-methylquinoline in ca. 10 cycles. The catalytic activity is slightly improved by increasing the reaction temperature or the ethylene pressure and strongly depends on the aniline/platinum ratio. The beneficial effects of added P(OMe)3 (2 equiv/PtBr2) or of a proton source (3 equiv/PtBr2) have also been pointed out. A gradual poisoning by N-ethylaniline has been observed, which could be minimized by using biphasic systems. The best result for the hydroamination with aniline (TON = 145 after 10 h at 150 °C) has been obtained in a biphasic system (n-Bu4PBr/decane) in the presence of C6H5NH3 + (3 equiv/PtBr2). The basicity of the arylamine has been shown to play an important role: the lower the basicity, the higher the TON. Thus, the hydroamination of ethylene with the weakly basic 2-chloroaniline in the presence of the PtBr2/H+ catalytic system (0.3% mol) for 72 h at 150 °C yields N-ethyl-2-chloroaniline as the sole reaction product (70% yield based on the amine charged) with TON = 250. When conducted with 1% of the above catalytic system, the reaction resulted in nearly quantitative conversion of 2-chloroaniline.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
PDF
