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From samples of moldy wall paint and damaged water-based paint, we isolated and quantified the density of microorganisms present in the samples and determined the morphology of the isolates; thereby, identifying the genera of the bacteria and mold strains. The results showed that the density of the strains collected from the wall paint samples was much higher than that of the water-based paint samples (106 CFU/mL and 104 CFU/mL, respectively). In the wall paint samples, only mold colonies were observed, not bacterial colonies, while in the water-based paint samples both mold and bacterial colonies appeared, although mold colonies were still predominant. Based on the observation of colony formation and microscopic morphology of molds, we classified six mold strains into five genera: Aspergillus sp., Cladosporum sp., Acremoium sp., Chaetomium sp., and Fusarium sp. The frequency of strains belonging to the genus Aspergillus sp. accounted for the majority in both wall and water-based paint samples. Among the three bacterial strains isolated, we identified two bacterial strains as G (-) and one strain as G (+).

This study studied the content and composition of the total lipid, lipid classes and fatty acids in 13 brown seaweed Sargassum species collected from Con Dao and Van Phong, Vietnam. The total lipid has a low content and varies among species from 0.10–1.70% of the fresh weight. From 13 species, seven lipid classes including polar lipid (Pol), free fatty acids (FFA), sterol (ST), hydrocarbon and wax (HW), triacylglycerol (TG), diacylglycerol (DG), and monoalkydiacylglycerol (MADG). Using the GC-FID technique, we have identified 29 fatty acids classified into 3 groups of saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids with an average content of 44.93%, 24.57% and 27.44%, respectively. Among those, many value fatty acids have been detected with high content such as C18:3n-3, C20:4n-6, 20:5n-3, and 22:6n-3. The lipid of 13 brown seaweed Sargassum species also fully contains omega-3,6,9 fatty acids with the content of 9.28%, 16.28% and 16.63%, respectively.

Alginate lyase is an enzyme that degrades alginate to create bioactive oligoalginate for application in medicine, industry, agriculture... In this study, cultural conditions of marine bacteria, Bacillus velezensis AlgSm1 have been investigated for producing alginate lyase with high content and activity. The nutritional components such as carbon source, nitrogen source, initial pH value, and cultural time were investigated. The results showed that the cultural conditions of B. velezensis AlgSm1 to biosynthesize alginate lyase with high activity were 5 mg/ml alginate, 0.8 mg/ml yeast extract; pH 5.5 and 18-hours fermentation at 28-30°C.

In this study, MCM-41 mesoporous silica nanoparticles were successfully synthesized by the condensation of a tetraorthosilicate precursor on a template self-assembled by cetyltrimethylammonium bromide in alkaline. The small-angle x-ray diffraction patterns of MCM-41 indicate that silica nanoparticles possess hexagonal structures with a high degree of structural ordering. Transmission electron microscopy images show that the size of the MCM-41 particles is around 100-120 nm, and the pore sizes range from 2 nm to 4 nm. In addition, the specific surface area of MCM-41 obtained by Brunauer–Emmett–Teller analysis is as high as 987 m2.g−1 and the pore size extracted from nitrogen physical adsorption isotherms is in accordance with the TEM result. Thermogravimetric analysis, Fourier-transform infrared spectroscopy, Zeta potential measurements and photoluminescence measurements show that 3-aminopropyltriethoxysilane (APTES) and doxorubicin were grafted and loaded successfully onto MCM-41 nanoparticles. An assay on fibroblasts, A549 and doxorubicin-resistant A549/DOX cells indicates that the prepared MCM41 grafting APTES nanoparticles are safe to normal cells and toxic to cancer cells in vitro.

Lobophora sp., belonging to brown macro algae phylum, is found in coral reefs. In this study, the fatty acid composition, lipid classes, polar lipid molecular forms, and bioactivities of this algae have been determined. It follows that five classes including polar lipid (Pol), sterol (ST), free fatty acids (FFA), triacylglycerol (TAG), and hydrocarbon and wax (HW), 23 fatty acids containing 5 PUFAs (ALA, GLA, AA, EPA, and DHA) and 157 molecular types of polar lipid group containing 48 phospholipid molecular forms belonging to 4 subclasses (PI (11), PC (14), PG (22), PA (1)), 45 glycolipid molecular forms classified into 3 subclasses of MGDG (8), DGDG (1), SQDG (36), and 64 betaine lipid molecular forms belonging to 2 subclasses (DGTA (37), DGTS (27)) have been identified for the first time from this algae. Furthermore, both polar lipid (PL) and unpolar lipid (UPL) show the NO inhibition activities with values of IC50 ranging from 52.10 to 66.21 µg/mL. Thus, lipid of this brown algae could promise to be a potential source for application in food, cosmetic, and pharmaceutic industry.

The title compound, C24H29NO4, is the product of a Petrenko–Kritchenko condensation of 1,5-bis(2-formylphenoxy)-3-oxapentane, pentan-3-one and methylammonium acetate in ethanol. The molecule has mirror symmetry. The aza-14-crown-3 ether ring adopts abowlconformation stabilized by a weak intramolecular C—H...O hydrogen bond. The conformation of the C—O—C—C—O—C—C—O—C polyether chain is t–g+–t–t–g−–t (t =trans, 180°; g =gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts achairconformation. The nitrogen atom has a trigonal–pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the molecules are linked by weak C—H...O interactions, forming zigzag chains propagating along the [100] direction.

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.

The thermal spray has been commonly used in several applications to replace the plating technology due to high adhesion, low cost, and environmental pollution. The thermal coating is usually used to rehibilitate the small disrepair of the crankshaft but the dimension and mechanical properties of such parts are still maintaned. Commonly, the microstructure and mechanical properties are greatly affected by depth of thermal coating, and thermal coating needs to be conducted the heat treatment to homogenize the microstructure between metals of coating and base metals as well as to improve the adhesion, hardness, and wear intensity. In this work, the effects of heat treatment on the microstructure and mechanical properties of the coating layer based on 80Ni-20Cr onto the surface of CT38 steel were conducted. SEM images and EDS analysis were used to determine the distribution of elements before and after heat treatment. In addition, mechanical properties such as Vicker hardness (HV), wear intensity, and adhesion were practically measured. As a result, after heat treatment by annealing under 1100oC during 8h, HV and adhesion were significantly higher than the case of non-heat treatment; meanwhile, wear intensity was found with 3 times lower compared to the unheated sample. The strong bi-lateral diffusion between Cr from coating layer and C from CT38 steel component to form carbide along with a formation of bond Ni-Fe was thought to be the main cause resulting in the improvement of mechanical properties and was demonstrated in this study.

Macrocyclic 22,24,25-trimethyl-8,11,14-trioxa-25-aza­tetra­cyclo­[19.3.1.02,7.015,20]penta­cosa-2,4,6,15 (20),16,18-hexaen-23-one obtained by a Petrenko–Kritchenko condensation of 1,5-bis­(2-formyl­phen­oxy)-3-oxa­pentane, pentan-3-one and methyl­ammonium acetate has been studied by X-ray structural analysis., The title compound, C24H29NO4, is the product of a Petrenko–Kritchenko condensation of 1,5-bis­(2-formyl­phen­oxy)-3-oxa­pentane, pentan-3-one and methyl­ammonium acetate in ethanol. The mol­ecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intra­molecular C—H⋯O hydrogen bond. The conformation of the C—O—C—C—O—C—C—O—C polyether chain is t–g+–t–t–g−–t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitro­gen atom has a trigonal–pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the mol­ecules are linked by weak C—H⋯O inter­actions, forming zigzag chains propagating along the [100] direction.

The silver embedded silica powders (Ag/SiO2) have been successfully prepared by sol-gel method. Ag nanoparticles were formed from the thermal decomposition of the silver nitrate. X-ray diffraction shows that the silver nanocrystals have appeared after a heat-treatment at 600 °C. TEM images show that the spherical silver particles with an average size around 30 nm dispersed homogeneously in silica matrix. The data of XRD, Raman and FTIR spectroscopy prove that the formation of the silver nanocrystals influent on the structural evolution of the silica matrix. The presence of metal nanocrystals leads to remarkable decrease in crystallizing temperature of SiO2. In addition, the adsorption-desorption analysis indicated that the growth of Ag particles makes the pores in silica structure widen.