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•The clogging and dilution of biogas depend on dissolved oxygen (DO).•pH depends on Sufur oxidizing bacteria (SOB), H2S solubility & DO.•Near-neutral or alkaline SOB (pH 7–8) are ...suitable bacteria for H2S removal.•Shutdown the biotrickling filters increases H2S removal & reduces biogas clogging.•The end-products in anoxic process depends on N/S ratio.
The presence of hydrogen sulfide (H2S) in biogas negatively affects human health and corrodes metal. Therefore, the removal of H2S from biogas before using is an essential requirement in many cases. Recently, biotrickling filters (BTFs) have been widely applied to the treatment of H2S on both laboratory and industrial scales. However, BTFs method also has some drawbacks such as low mass transfer efficiency, clogging the bed filter due to further elemental sulfur (S) excess accumulation, and biogas dilution. This paper reviews the recent development of aerobic BTF systems and solutions for those limitations during the H2S oxidation process in biogas. In addition, the factors affecting H2S removal efficiency, including sulfur-oxidizing bacteria, biofilm, packing material, pH, dissolved oxygen (DO), empty bed retention time (EBRT), ingredients of nutrients for the growth of bacteria, trickling liquid and gas velocity, are also discussed. Finally, the current strength of research in the field of H2S removal in biogas using BTF and its future prospects are also suggested. Some of highest elimination capacity (EC) of 78.57 g H2S/m3h, 144 g H2S/m3h, 228.6 g H2S/m3h were obtained from previous experiments.
Adenosma bracteosum and Vitex negundo are natural sources of methoxylated flavonoids. Little is known about the α‐glucosidase inhibition of multi‐methoxylated flavonoid derivatives. Eighteen natural ...flavonoids were isolated from A. bracteosum and V. negundo. Seven halogenated derivatives were synthesized. Their chemical structures were elucidated by extensive NMR analysis and high‐resolution mass spectroscopy as well as comparisons in literature. All compounds were evaluated for their α‐glucosidase inhibition. Most compounds showed good activity with IC50 values ranging from 16.7 to 421.8 μM. 6,8‐Dibromocatechin was the most active compound with an IC50 value of 16.7 μM. A molecular docking study was conducted, indicating that those compounds are potent α‐glucosidase inhibitors.
In this investigation, cobalt ferrite nanoparticles (CFO NPs) were synthesized using a hydrothermal method. Then, silver nanoparticles (Ag NPs) were decorated on CFO NPs to form Ag/CFO NPs using ...jasmine extract as a reducing agent of Ag
+
ions. The properties of Ag/CFO NPs were characterized by X-ray powder diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, vibrating sample magnetometry, and catalytic tests in non-radiation conditions. The catalytic results indicated that the Ag/CFO NPs could activate peroxymonosulfate to generate sulfate radicals for the decomposition of different dyes such as methylene blue, methyl orange, and rhodamine B. For the Ag/CFO sample, Ag NPs validated the roles in dye adsorption, reduction of 4-nitrophenol, and improvement of antibacterial behavior. The growth inhibition activity of Ag/CFO NPs was observed against
Pseudomonas aeruginosa
(18.18 ± 2.48 mm) and
Staphylococcus aureus
(10.14 ± 0.72 mm). Furthermore, Ag/CFO NPs displayed good reusability after three consecutive runs. Therefore, Ag/CFO material is shown to be a potential multifunctional catalyst in wastewater treatment.
Ag/CFO NPs as a reusable multifunctional catalyst were fabricated using jasmine extract as a reducing agent of Ag⁺ ions. In this material, CFO NPs were vital in degrading various dyes; Ag NPs validated the roles in dye adsorption, reduction of 4-nitrophenol, and antibacterial activity.
•Structures of fucoidans from S. crassifolium and P. australis were determined.•Molecular models of the fucoidans were built based on chemical structure.•Intestinal immunological activity via Peyer’s ...patch cells of the fucoidans was estimated.•A better understanding on structure-activity relationship of fucoidan was proposed.
We studied the structure of fucoidans extracted from two brown seaweed species, Sargassum crassifolium and Padina australis, and their intestinal immunomodulating activity via Peyer’s patch cells of C3H/HeJ mice. ESI–MS analysis indicated that the dominant structure of both fucoidans has a backbone of α-(1→4)-linked and α-(1→3)-linked l-fucose residues and sulfate groups are attached at the C-2 and C-4 positions; branches of fucoidan from S. crassifolium are galactose residues with (1→4)- linkage and branching points are at C-4 of fucose, while fucoidan from P. australis, branches are sulfated galactose-fucose disaccharides and sulfated galactose monosaccharides attached to the main chain through (1→3)- or (1→4)- linkages. According to small angle X-ray scattering (SAXS) measurements, the two fucoidans have a branched structure. We simulated them with molecular models based on our proposed primary structure. These fucoidan samples have the ability to stimulate intestinal immunological activity via Peyer’s patch cells.
A chemical investigation of K. heteroclite led to isolation of two new dibenzocyclooctadienes (1 and 2) together with 14 known compounds (3-16) by using multiple chromatographic techniques. New ...compounds (1 and 2) were obtained and identified by spectroscopic methods (HRESIMS, 1D and 2D NMR, and ECD) as well as by comparison of their experimental data with those reported in the literatures. All the isolates were evaluated for their ability to modulate TNF-α production in lipopolysaccharide (LPS) stimulated RAW264.7 cells. Among them, compound 5 displayed the most inhibition against tumor necrosis factor (TNF)-α production with IC50 value of 6.16±0.14 µM. Whereas, compounds (1, 3, and 6) showed the significant inhibition (IC50 values ranging from 9.41 to 14.54 µM), and compounds (2, 4, 9, 10, 13, 15, and 16) exhibited moderate inhibition (IC50 values ranging from 19.27 to 40.64 µM) toward TNF-α production, respectively.
The aim of this study is to elucidate the structure and investigate the antimicrobial activity of an ulvan obtained by water extraction from green seaweed Ulva reticulata collected at Nha Trang sea ...of Vietnam by using IR, NMR, SEC-MALLS and SAXS methods. The ulvan is composed of rhamnose, galactose, xylose, manose and glucose (mole ratio Rha: Gal: Xyl: Man: Glu = 1:0.12:0.1:0.06:0.03), uronic acid (22.5%) and sulphate groups (17.6%). Chemically structural determination showed that the ulvan mainly composed of disaccharide →4)β-D-GlcA(1→4)α-L-Rha3S-(1→. The results from SAXS indicated that ulvan under study has a rod-like bulky chain conformation. Ulvan from U. reticulata showed high antimicrobial activity, with inhibition zone diameter of 20 mm against Enterobacter cloace and 18 mm against Escherichia coli.
Adsorption of the polyelectrolyte polydiallyldimethylammonium chloride (PDADMAC) onto nanosilica (SiO₂) fabricated from rice husk was studied in this work. Nanosilica was characterized by X-ray ...diffraction, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Adsorption of PDADMAC onto SiO₂ increased with increasing pH because the negative charge of SiO₂ is higher at high pH. Adsorption isotherms of PDADMAC onto silica at different KCl concentrations were fitted well by a two-step adsorption model. Adsorption mechanisms of PDADMAC onto SiO₂ are discussed on the basis of surface charge change, evaluation by ζ potential, surface modification by FTIR measurements, and the adsorption isotherm. The application of PDADMAC adsorption onto SiO₂ to remove amoxicillin antibiotic (AMX) was also studied. Experimental conditions such as contact time, pH, and adsorbent dosage for removal of AMX using SiO₂ modified with PDADMAC were systematically optimized and found to be 180 min, pH 10, and 10 mg/mL, respectively. The removal efficiency of AMX using PDADMAC-modified SiO₂ increased significantly from 19.1% to 92.3% under optimum adsorptive conditions. We indicate that PDADMAC-modified SiO₂ rice husk is a novel adsorbent for removal of antibiotics from aqueous solution.
Fucoidans are sulfated, fucose-rich marine polysaccharides primarily found in cell walls of brown seaweeds (macroalgae). Fucoidans are known to possess beneficial bioactivities depending on their ...structure and sulfation degree. Here, we report the first functional characterization and the first crystal structure of a prokaryotic sulfatase, PsFucS1, belonging to sulfatase subfamily S1_13, able to release sulfate from fucoidan oligosaccharides. PsFucS1 was identified in the genome of a Pseudoalteromonas sp. isolated from sea cucumber gut. PsFucS1 (57 kDa) is Ca
dependent and has an unusually high optimal temperature (68 °C) and thermostability. Further, the PsFucS1 displays a unique quaternary hexameric structure comprising a tight trimeric dimer complex. The structural data imply that this hexamer formation results from an uncommon interaction of each PsFucS1 monomer that is oriented perpendicular to the common dimer interface (~ 1500 Å
) that can be found in analogous sulfatases. The uncommon interaction involves interfacing (1246 Å
) through a bundle of α-helices in the N-terminal domain to form a trimeric ring structure. The high thermostability may be related to this unusual quaternary hexameric structure formation that is suggested to represent a novel protein thermostabilization mechanism.
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•ZnO nanorods were prepared by galvanic effect assisted hydrothermal process.•Gold nanoparticles were decorated on the as-prepared nanorods by sputtering method.•The Au nanoparticles ...enhance photoluminescence, Raman scattering and photocatalytic properties of ZnO nanorods.•ZnO@Au SERS substrates offer high enhancement factor, high uniformity, and recyclability.
Raman is a very useful tool to identify chemical substances. However, Raman signal is normally not very strong and hence it is important to fabricate surface enhance Raman scattering (SERS) substrates of good repeatability and high enhancement factor. In this study, ZnO nanorods were prepared by a facile hydrothermal process assisted with galvanic effect. Gold nanoparticles were decorated on the as-prepared nanorods by sputtering method. The results showed that the Au nanoparticles enhance photoluminescence, Raman scattering and photocatalyst properties of ZnO nanorods. The ZnO@Au based SERS substrate showed high enhancement factor and can detect methylene blue at low concentration of 10–9 M. In combination with self cleaning under UV irradiation, the ZnO@Au SERS substrates can be reusable and hence it is promising for quantitative analyzing based on Raman scattering.
Although umbilical cord blood (UCB) is identified as a source of mesenchymal stem cells (MSCs) with various advantages, the success in cell isolation is volatile. Therefore, it is necessary to ...optimize methods of cord blood-derived MSC (UCB-MSC) isolation and culture. In this study, we evaluated the efficiency of UCB-MSC isolation and expansion using different commercially available serum- and xeno-free media and investigated the capacity of autologous serum and plasma as a supplement to support cell proliferation. Additionally, we defined the presence of multilineage-differentiating stress-enduring (Muse) cells in the UCB-MSC population. Functions of UCB-MSC in in vitro angiogenesis processes and anti-cancer were also verified.
Mononuclear cells were isolated using density gradient separation and cultured in four commercial media kits, as well as four surface coating solutions. UCB-MSCs were characterized and tested on tube formation assay, and co-cultured with SK-MEL cells in a transwell system.
The results showed that only StemMACS™ MSC Expansion Media is more appropriate to isolate and culture UCB-MSCs. The cells exhibited a high cell proliferation rate, CFU forming capability, MSC surface marker expression, trilineage differentiate potential, and chromosome stability. In addition, the culture conditions with autologous serum coating and autologous plasma supplement enhanced cell growth and colony forming. This cell population contained Muse cells at rate of 0.3%. Moreover, UCB-MSCs could induce the tube formation of human umbilical vein endothelial cells and inhibit more than 50% of SK-MEL cell growth.
UCB-MSCs could be high-yield isolated and expanded under serum- and xeno-free conditions by using the StemMACS™ MSC Expansion Media kit. Autologous serum coating and plasma supplement enhanced cell proliferation. These UCB-MSCs had effected the tube formation process and an anti-cancer impact.
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