The Antibacterial Activity of Ta-doped ZnO Nanoparticles

A novel photocatalyst of Ta-doped ZnO nanoparticles was prepared by a modified Pechini-type method. The antimicrobial study of Ta-doped ZnO nanoparticles on several bacteria of Gram-positive Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) were performed using a standard microbial method. The Ta-doping concentration effect on the minimum inhibitory concentration (MIC) of various bacteria under dark ambient has been evaluated. The photocatalytical inactivation of Ta-doped ZnO nanoparticles under visible light irradiation was examined. The MIC results indicate that the incorporation of Ta⁵⁺ ions into ZnO significantly improve the bacteriostasis effect of ZnO nanoparticles on E. coli, S. aureus, and B. subtilis in the absence of light. Compared to MIC results without light irradiation, Ta-doped ZnO and pure ZnO nanoparticles show much stronger bactericidal efficacy on P. aeruginosa, E. coli, and S. aureus under visible light illumination. The possible antimicrobial mechanisms in Ta-doped ZnO systems under visible light and dark conditions were also proposed. Ta-doped ZnO nanoparticles exhibit more effective bactericidal efficacy than pure ZnO in dark ambient, which can be attributed to the synergistic effect of enhanced surface bioactivity and increased electrostatic force due to the incorporation of Ta⁵⁺ ions into ZnO. Based on the antibacterial tests, 5 % Ta-doped ZnO is a more effective antimicrobial agent than pure ZnO.     

Novel Ester-linked Anionic Gemini Surfactant: Synthesis,Surface-Active Properties and Antimicrobial Study

A novel anionic gemini surfactant containing an ester bond in the spacer group was synthesized using cardanol as the raw material and characterized by IR, ¹H NMR and ¹³C NMR. The surface properties of the gemini surfactant were investigated and compared with its corresponding single chain surfactant counterpart. It was found that this novel gemini surfactant exhibited a low critical micelle concentration value (1.9 mM) and good efficiency in reducing surface tension of water (33.6 mN/m). The gemini surfactant was found to have antimicrobial activity against Gram-negative (Escherichia coli and Pseudomonas aeruginosa), Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria and fungi (Aspergillus niger, Aspergillus flavus, Candida albicans and Rhizopus stolonifer). The gemini as well as the corresponding single chain surfactant showed good antimicrobial activity against all pathogenic microorganisms studied and can be employed as an antimicrobial agent. The synthesized novel anionic gemini surfactant possesses an excellent wettability and low foamability.     

Cyclodextrin-based hyperbranched polyester: synthesis,characterization, and antimicrobial activity

In this study, the synthesis of cyclodextrin-based hyperbranched polyester (CD-based HBPE) was prepared by a simple condensation route via acid chloride approach (Scheme 1). The formation of ester linkages in CD-based HBPE was clearly identified from FTIR and NMR spectroscopy. The resulting structure and the molecular weight of the CD-based HBPE were confirmed with LC–MS analysis. The CD-based HBPE displayed the fluorescence maxima in the 425 nm range with relatively narrow peak widths indicating that they had pure and intense fluorescence. The antimicrobial activity of the CD-based HBPE was evaluated against the Gram-negative organisms like Escherichia coli and Salmonella paratyphi, Gram-positive organisms as Bacillus subtilis and Staphylococcus aureus and fungi such as Aspergillus niger, and Candida albicans. CD-based HBPE showed a great inhibitory effect toward both bacteria and fungi. The microorganism which possess greater antimicrobial activity with standard antibiotics was selected for determining the minimum inhibitory concentration (MIC) value of the CD-based HBPE. Therefore, the MIC value of the CD-based HBPE against B. subtilis was tested and found to be 31.25 μg mL^?1. Hence, it is suggested that CD-based HBPE holds good agreement with the antimicrobial assay.     

Facile preparation and good performance of nano-Ag/metallocene polyethylene antibacterial coatings

Metallocene polyethylene/nano-silver coatings were prepared by a facile air-spray method on polymer films. Different from the prevailing strategy to endow polyethylene with antibacterial performance, we used metallocene polyethylene sol and nano-silver as a precursor to deposit coatings on polymers at a relatively low operating temperature. Antibacterial coatings with excellent mechanical properties, water resistance, and low silver release were achieved. The composite coatings were examined in terms of surface characteristics, mechanical properties, and antibacterial activity against two representative bacterial strains including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The composite coatings exhibited favorable microstructure, good mechanical properties, and suitable crystallinity. The antimicrobial tests indicated that the fabricated composite coatings showed promising antibacterial activity against E. coli and S. aureus. Furthermore, Ag ions released by the composite coating after 30 days were under 1.2 ppb. These results indicated a promising prospect of the composite coating for wide antibacterial applications.     

IR Spectroscopy in Rank and Group Assignment of Coal

The possibility of express determination of the characteristics V _IR ^daf , R_{o, IR}, y_IR, ΣLC_IR, and A _IR ^d used in the ranking of coal on the basis of IR spectroscopy is assessed for a specific example: Kuznetsk coals of different maceral composition and metamorphic development. The IR characteristics are compared with values obtained by standard methods (V^daf, R_{o, r, y}, ΣLC, and A^d).     

Manufacturing and structural analysis of antimicrobial kefiran/polyethylene oxide nanofibers for food packaging

Kefiran, a branched glucogalactan, is a useful microbial polysaccharide produced by lactic acid bacteria. The aim of this study was to evaluate the antimicrobial activity of kefiran nanofibers as a biocontrol agent for food packaging as well as food preservation. Thus, kefiran/polyethylene oxide (PEO) nanofibers were fabricated using the electrospinning method. Kefiran was produced from raw milk with 0.5% fat and 10 g of kefir grain and was separated from it by ethanol. Structural analysis of kefiran was detected by means of nuclear magnetic resonance and Fourier transforms infrared spectroscopy (FTIR). Antimicrobial properties of kefiran were assayed against Rhizoctonia, Pseudomonas sp. (isolated from soil at Isfahan University) and Staphylococcus aureus (S. aureus). Electrospun kefiran/PEO nanofibers were characterized by scanning electron microscopy, optical microscopy and ATR-FTIR techniques. Hydrophilicity and in vitro biodegradation of the kefiran/PEO nanofibers were investigated, as well. The results showed that the mean diameter of the nanofibers was 607.5 nm. The contact angle measurement result was 51.5° ± 0.71 with normal hydrophilicity. First of all, antimicrobial properties of kefiran were confirmed against different types of microorganisms. Moreover, the result obtained in this study showed that kefiran/PEO nanofibers with oxidizing functional groups on them have antimicrobial activity against S. aureus. Biodegradation of kefiran/PEO nanofibers was also confirmed by FTIR.     

Ignition temperature of coal. 1. Influence of the coal’s composition,structure, and properties

The reactions of coal with the materials used in determining the ignition temperature of unoxidized coal according to Ukrainian State Standard DSTU 7611:2014 are analyzed. First, the ignition temperature of various types of coal from Ukraine, Russia, Canada, Australia, the Czech Republic, Poland, and Indonesia is determined. The influence of the composition, structure, and properties of the coal on its ignition temperature is assessed. The ignition temperature of the unoxidized coal is found to be closely related to the content of organic carbon C^daf and aromatic carbon C_ar, the structural parameter δ characterizing the degree of saturation of the coal’s organic mass, and also the vitrinite reflection coefficient R_o and the yield of volatiles V^daf.     

Antibacterial Activity of Alanine-Derived Gemini Quaternary Ammonium Compounds

The antibacterial activity of alanine-derived gemini quaternary ammonium salts (chlorides and bromides) with various spacer and alkyl chain lengths was investigated. The studied compounds exhibited a strong bactericidal effect, especially bromides with 10 and 12 carbon alkyl chains and 3 carbon spacer groups (TMPAL-10 Br and TMPAL-12 Br), with a short contact time. Both salts dislodged biofilms of Pseudomonas aeruginosa and Staphylococcus epidermidis, and were lethal to adherent cells of S. epidermidis. Bromide with 2 carbon spacer groups and 12 carbon alkyl chains (TMEAL-12 Br) effectively reduced microbial adhesion by coating polystyrene and silicone surfaces. The results obtained suggest that, after further studies, gemini QAS might be considered as antimicrobial agents in medicine or industry.     

Deodorizing,antimicrobial and glucosyltransferase inhibitory activities of polyphenolics from biosource

We evaluated the deodorizing activities of polyphenolics against methyl mercaptan and their inhibitory activity on Streptococcus mutans, Candida albicans, and glucosyltransferase responsible for oral health. Polyphenolics including eckol, dieckol, catechol, catechin, phloroglucinol, chlorogenic acid, epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), caffeic acid, and tannic acid were used to investigate their deodorizing, antimicrobial and enzyme activity. Among the polyphenolics, dieckol, eckol, and catechol showed higher deodorizing activity against methyl mercaptan than sodium copper chlorophyllin known as a commercial deodorant. Catechol, dieckol, and eckol exhibited a strong antimicrobial activity on S. mutans, while cinnamic acid, caffeic acid, and catechol showed a strong antifungal activity on C. albicans compared to other polyphenolics. Tannic acid, ECG, and dieckol strongly inhibited the activity of the glucosyltransferase produced by Streptococcus mutans.     

Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere – Herbivore Interface

Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.     

Properties of the solid thermolysis products of brown coal impregnated with an alkali

The mechanism of formation of a porous active carbon framework is considered, and the properties of the solid thermolysis products of brown coal (Aleksandriisk deposit, Ukraine) with potassium hydroxide are studied. The yields of the solid thermolysis products (Y _STP, %) and potassium humates, the rate of the interaction of the solid thermolysis products with KOH at 700–900°C, the specific surface areas (S _BET, m²/g), the adsorption capacities for methylene blue (A _MB, mg/g) and iodine (A _I, mg/g), and the specific activities of surface areas A _MB ^′ = A _MB/S _BET and A _I ^′ = A _I/S _BET (mg/m²) are determined under variation of the KOH/coal ratio (R _KOH < 18 mol/kg) and temperature (110–900°C).     

Thermal properties and crystallization behaviors of polylactide/redwood flour or bamboo fiber composites

A series of polylactide/redwood flour (PLA/RWF) and polylactide/bamboo fiber (PLA/BF) composites were successfully prepared using a solution mixing procedure. Fourier transform infrared spectroscopy (FTIR) and wide-angle X-ray diffraction (XRD) were employed to characterize these composites. Thermal properties and crystallization behaviors of PLA composites were determined by their respective techniques of differential scanning calorimetry (DSC) and polarized optical microscopy (POM). With the increasing content of fibers, the glass transition temperature (T _g ), crystallization temperature (T _c ), and melting temperature (T _m ) of PLA/RWF composites decreased first and then increased, but T _g and T _m of PLA/BF composites increased first and decreased afterwards. It is suggested that fibers could improve the segmental mobility of PLA; meanwhile, the different morphologies, sizes, and densities of RWF and BF have different effects on thermal properties of composites. Under the increasing content of RWF, the crystallization rate of the composite increased first and decreased afterwards. When the content of RWF was 5%, the crystallization rate was at its maximum. It could be possible that the addition of fibers was able to nucleate PLA and increase the degree of crystallinity, but the excess content of fibers easily led to heterogeneous composites and subsequent poor crystallization behaviors. In a word, thermal properties and crystallization behaviors of PLA composites were regularly changing by increasing content of fibers.     

Predicting the classification characteristics of coal. Part 3. Gross calorific value of dry,ash-free coal

For 63 samples of Ukrainian, Russian, and imported coal, equations for predicting the gross calorific value Q_s^daf on the basis of the following coal characteristics are developed: W^a, O_d^daf, Q_s^af, and C_ar. The error is within the standard tolerances (σ ≤ 0.3 MJ/kg). With sufficient accuracy, Q_s^daf may be predicted from equations based on petrographic characteristics such as the vitrinite reflectance, the content of liptinitegroup minerals, and the sum of lean macerals (I + 2Sv/3). In these equations, the coefficients correspond to the heat of combustion of the vitrinite components at different metamorphic stages, the liptinite, and the lean macerals.     

Synthesis of silver nanoparticles modified with lysozyme and sodium dioctyl sulfosuccinate and comparison of their biological activities

Silver nanoparticles have been fabricated by the method of chemical reduction in solution using different types of stabilizers: an organic low-molecular compound—sodium dioctyl sulfosuccinate (AOT)— and a natural biologically active substance—antimicrobial cationic polypeptide lysozyme. According to studies of the produced hydrosols, the average size of the shell-coated particles is 20–25 nm. The biological activity of the obtained bioconjugates toward Gram-negative (Escherichia coli ML35p, Pseudomonas aeruginosa (clinical isolate)) and Gram-positive (Listeria monocytogenes EGD (АТСС ВАА-679), MRSA ATCC 33591 (Staphylococcus aureus resistant to methicillin)) bacteria has been investigated by the methods of radial diffusion in an agarose gel and serial dilution in a liquid nutritional medium. It has been established that the antimicrobial activity of the bioconjugates depends on the nature of the used stabilizer.     

Assessing the technological value of coal in coking

Coking coal of the same rank from different countries and fields may be distinguished in terms of use value by rating on the basis of seven technological and petrographic characteristics that determine the coke yield and properties: the ash content A^d; the total sulfur content S_t^d; the yield of volatiles V^daf; the plastic-layer thickness y; the vitrinite reflection coefficient R_o; the content of vitrinite-group macerals Vt; and the basicity index B_b. A range of values and a rating (on a scale from 1 to 10) are established for each of these parameters. Each rating corresponds to a particular score (from 0.1 to 1.0). Ranges of A^d, S_t^d, Vt, and B_b are established for the whole metamorphic series, while ranges of V^daf, y, and R_o are established for individual ranks and groups of ranks. Altogether, 105 coking coals from Ukraine, Russia, the United States, Australia, and Canada that are used at Ukrainian coke plants are investigated. The range of rating scores and their mean values are determined for individual coal ranks and groups. As an example, three bituminous coals from Ukraine, the United States, and Australia are compared by the proposed method. This method permits objective assessment of the technological value of coal within a single rank and the selection of the best purchase option.     

Mineral content in fishes in the lower course of the itapecuru river in the state of Maranhão,Brazil

Concentrations of calcium, iron, potassium, magnesium, phosphorus, zinc, copper, selenium and nickel were determined in the muscle tissue of seven species of fish (Plagioscion squamosissimus, Geophagus surinamensis, Prochilodus lacustres, Curimata sp., Schizodon dissimilis, Ageneiosus ucayalensis and Hypostomus plecostomus) collected from the lower course of the Itapecuru River in the state of Maranhão, Brazil. The samples were digested in a nitricperchloric solution and analyzed using an inductively coupled plasma atomic emission spectrometer, with the construction of specific calibration curves for each element. The highest concentrations of constituent minerals were found for phosphorus, potassium, nickel and magnesium (399.83, 144.60, 90.20 and 29.49 mg 100 g^?1, respectively) in G. surinamensi, P. lacustres and Curimata sp. The lowest concentrations were found for copper, zinc, iron and selenium (0.12, 0.51, 1.05 and 8.31 mg 100 g^?1, respectively) in Curimata sp., S. dissimilis, A. ucayalensis and P. squamosissimus. The concentrations of all minerals can be considered low and are below the maximum limit established by Brazilian legislation for the human ingestion of fish meat. A comparison of the seven species of fish investigated revealed no statistically significant differences regarding the concentrations of minerals, suggesting that size and different dietary habits do not exert an influence on absorption. The low concentrations of metals, such as Fe, Cu, Zn and Ni, may be related to the environmental conditions of the mouth of the river, which receives ocean inputs that produce particular tide cycles with a strong dispersion capacity, thereby diminishing residence time in the water column and reducing the availability of these metals to species of fish.     

Phytofabrication,Characterization and Antibacterial Activity of <Emphasis Type="Italic">Cassia auriculata</Emphasis> Leaf Extract Derived CuO Nanoparticles

A simple, eco-friendly phytosynthesis of copper oxide nanoparticles (CuO NPs) using Cassia auriculata leaf extract was reported. The prepared CuO NPs was characterized by UV–vis spectroscopy which exhibited the surface plasmon resonance (SPR) band at 380–385 nm. TEM and EDX analysis confirmed that CuO NPs were spherical and in size range of 30–35 nm with identified elements Cu and O. X-ray diffraction (XRD) spectrum showed the crystalline nature of the prepared CuO NPs. FTIR spectrum confirmed the presence of Cu–O functional groups. CuO NPs showed significant antibacterial efficacy against all the tested bacterial strains, i.e., Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. CuO NPs showed strong antibacterial action against B. subtilis and E. coli than P. aeruginosa and S. aureus. The results of this study revealed that C. auriculata leaf extract was found to be an effective bio-reducing agent for CuO NPs synthesis and also the antibacterial efficacy of phytofabricated CuO may be useful for its applications in medical and textile industries.     

Sex-Pairing Pheromones in Three Sympatric Neotropical Termite Species (Termitidae: Syntermitinae)

Termite colonies are almost always founded by a pair of winged dispersers, in spite of the high costs and low success rates inherent in independent colony foundation. The dispersal flights of imagoes from natal colonies are followed by mate search, mediated by sex-pairing pheromones. Here, we studied the chemistry of sex-pairing pheromones and the related aspects of mate search in winged imagoes of two facultatively parthenogenetic species, Embiratermes neotenicus and Silvestritermes minutus, and an additional species from the same subfamily, Silvestritermes heyeri. All three species are widespread in the Neotropics, including the rainforests of French Guiana. After the dispersal flight and spontaneous loss of wings, females expose their hypertrophied tergal glands situated under abdominal tergites VIII – X. The females are attractive to males and, upon direct contact, the two sexes form characteristic tandems. Chemical analyses indicated that the females secrete species-specific combinations of unbranched, unsaturated C₁₂ primary alcohols from the tergal glands, (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol (approx. 200 pg per female) and (3Z)-dodec-3-enol (185 pg) in E. neotenicus, (3Z,6Z)-dodeca-3,6-dien-1-ol (3500 pg) in S. heyeri, and (3Z,6Z)-dodeca-3,6-dien-1-ol (300 pg) and (3Z)-dodec-3-enol (50 pg) in S. minutus. (3Z,6Z,8E)-Dodeca-3,6,8-trien-1-ol and (3Z,6Z)-dodeca-3,6-dien-1-ol act as major pheromone components in the respective species and mimic the function of female tergal gland extracts in electrophysiological and behavioral experiments. Biologically relevant amounts of the third compound, (3Z)-dodec-3-enol, elicited non-significant reactions in males of E. neotenicus and S. minutus, and slight synergistic effects in males of S. minutus when tested in combination with the major component.     

Inducible <Emphasis Type="Italic">De Novo</Emphasis> Biosynthesis of Isoflavonoids in Soybean Leaves by <Emphasis Type="Italic">Spodoptera litura</Emphasis> Derived Elicitors: Tracer Techniques Aided by High Resolution LCMS

Isoflavonoids are a characteristic family of natural products in legumes known to mediate a range of plant-biotic interactions. For example, in soybean (Glycine max: Fabaceae) multiple isoflavones are induced and accumulate in leaves following attack by Spodoptera litura (Lepidoptera: Noctuidae) larvae. To quantitatively examine patterns of activated de novo biosynthesis, soybean (Var. Enrei) leaves were treated with a combination of plant defense elicitors present in S. litura gut content extracts and L-α-[¹³C₉, ¹⁵N]phenylalanine as a traceable isoflavonoid precursor. Combined treatments promoted significant increases in ¹³C-labeled isoflavone aglycones (daidzein, formononetin, and genistein), ¹³C-labeled isoflavone 7-O-glucosides (daidzin, ononin, and genistin), and ¹³C-labeled isoflavone 7-O-(6″-O-malonyl-β-glucosides) (malonyldaidzin, malonylononin, and malonylgenistin). In contrast levels of ¹³C-labeled flavones and flavonol (4′,7-dihydroxyflavone, kaempferol, and apigenin) were not significantly altered. Curiously, application of fatty acid-amino acid conjugate (FAC) elicitors present in S. litura gut contents, namely N-linolenoyl-L-glutamine and N-linoleoyl-L-glutamine, both promoted the induced accumulation of isoflavone 7-O-glucosides and isoflavone 7-O-(6″-O-malonyl-β-glucosides), but not isoflavone aglycones in the leaves. These results demonstrate that at least two separate reactions are involved in elicitor-induced soybean leaf responses to the S. litura gut contents: one is the de novo biosynthesis of isoflavone conjugates induced by FACs, and the other is the hydrolysis of the isoflavone conjugates to yield isoflavone aglycones. Gut content extracts alone displayed no hydrolytic activity. The quantitative analysis of isoflavone de novo biosynthesis, with respect to both aglycones and conjugates, affords a useful bioassay system for the discovery of additional plant defense elicitor(s) in S. litura gut contents that specifically promote hydrolysis of isoflavone conjugates.     

A Comprehensive Study on the Synthesis and Micellization of Disymmetric Gemini Imidazolium Surfactants

Two groups of disymmetric Gemini imidazolium surfactants, [C₁₄C₄C _m im]Br₂ (m = 10, 12, 14) and [C _m C₄C _n im]Br₂ (m + n = 24, m = 12, 14, 16, 18) surfactants, were synthesized and their structures were confirmed by ¹H NMR and ESI–MS spectroscopy. Their adsorption at the air/water interface, thermodynamic parameters and aggregation behavior were explored by means of surface tension, electrical conductivity and steady-state fluorescence. A series of surface activity parameters, including cmc, γ _cmc, π _cmc, pC ₂₀, cmc/C ₂₀, Γ _max and A _min, were obtained from surface tension measurements. The results revealed that the overall hydrophobic chain length (N _c) for [C₁₄C₄C _m im]Br₂ and the disymmetry (m/n) for [C _m C₄C _n im]Br₂ had a significant effect on the surface activity. The cmc values decreased with an increase of N _c or m/n. The thermodynamic parameters of micellization (ΔG _m ^θ , ΔH _m ^θ , ΔS _m ^θ ) derived from the electrical conductivity indicated that the micellization process of [C₁₄C₄C _m im]Br₂ and [C _m C₄C _n im]Br₂ was entropy-driven at different temperatures, but the contribution of ΔH _m ^θ to ΔG _m ^θ was enhanced by increasing N _c or m/n. The micropolarity and micellar aggregation number (N _agg) were estimated by steady-state fluorescence measurements. The results showed that the surfactant with higher N _c or m/n can form larger micelles, due to a tighter micellar structure.