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H-ZSM-5 zeolites are successfully synthesized within 1 h with an organic template free system by the seed-assisted method. The synthetic method not only reduces the production cost of H-ZSM-5 zeolite, but also decreases the environmental pollution produced compared with that of the conventional synthesis process. Characterization by SEM, XRD, [N.sub.2] adsorption-desorption, N[H.sub.3]-TPD, and Py-IR confirms that the H-ZSM-5 product has a high crystallinity and reveals that the rapid synthesis process is in accordance with the seed surface crystallization mechanism. To improve the aromatic selectivity on the H-ZSM-5 zeolite, different concentrations of Mo and Zn catalysts were prepared by incipient wetness impregnation and the ion-exchange method. Mo-Zn/H-ZSM-5-SAS-1 h have similar catalytic lifetimes and higher selectivity of paraxylene in aromatic products compared with Mo-Zn/H-ZSM-5-seed in the reaction of methanol to aromatic. However, the catalytic lifetime of 6%Mo/H-ZSM-5-SAS-1 h is shorter than that of the 6%Mo/H-ZSM-5-seed catalyst in methane to benzene reaction under the same reaction conditions. Key words: rapid synthesis, H-ZSM-5, organic template free, seed-assisted, aromatization. Nous avons reussi a synthetiser des zeolithes H-ZSM-5 en 1 h dans un systeme sans agent structurant organique par la methode assistee par ensemencement. La methode de synthese que nous avons employee permet non seulement de reduire le cout de production de la zeolithe HZSM5, mais egalement de prevenir la pollution environnementale comparativement au procede de synthese classique. La caracterisation par microscopie electronique a balayage (MEB), diffraction des rayons X (DRX), adsorption-desorption de [N.sub.2], desorption thermoprogrammee d'ammoniac (N[H.sub.3]DTP) et pyrolyse couplee a la spectroscopie infrarouge (PylR) revele que le processus de synthese rapide est en accord avec le mecanisme de cristallisation par ensemencement de la surface. Afin d'ameliorer la selectivite aromatique de la zeolithe HZSM5, nous avons prepare des catalyseurs a differentes concentrations de Mo et de Zn par impregnation a humidite naissante et echange d'ions. Le catalyseur Mo-Zn/HZSM5SAS1 h a une duree de vie catalytique similaire et une selectivite parmi les produits aromatiques plus elevee pour le paraxylene que le catalyseur MoZn/HZSM5seed dans la reaction d'aromatisation du methanol. Cependant, la duree de vie catalytique du catalyseur 6%Mo/HZSM5SAS1 h est plus courte que celle du catalyseur 6%Mo/HZSM5seed dans la reaction d'aromatisation du methane en benzene dans les memes conditions de reaction. [Traduit par la Redaction] Mots-cles: synthese rapide, H-ZSM-5, sans agent structurant organique, assistee par ensemencement, aromatization., 1. Introduction Aromatic hydrocarbons are important chemical intermediates in the fine chemical industry and have huge industrial demand. (1) In recent decades, the methanol to aromatics (MTA) and methane to [...]

The ZnIn/HZSM-5 catalyst was prepared by the wetness impregnation method, and the structure of catalyst was characterized by XRD, SEM, TEM, [H.sub.2]-TPR, N[H.sub.3]-TPD, XPS, TG, and [N.sub.2] adsorption-desorption and then investigated in the coupling of propane with C[O.sub.2] to propylene. It is found that the addition of Zn species is beneficial to the dispersion of [In.sub.2][O.sub.3] over HZSM-5, which plays an important role in propene formation, and adjusts the acidity distribution of In/HZSM-5 catalyst, aswell assignificantly improves the activity of In/HZSM-5 catalyst. The selectivity of propylene is 68.21% in the coupling of propane with C[O.sub.2] over ZnIn/HZSM-5 catalyst when the time on stream (TOS) is 2 h, reaction temperature is 580 [degrees]C, reaction pressure is 0.3 MPa, [C.sub.3][H.sub.6]:C[O.sub.2]:[N.sub.2] = 1:4:5, catalyst mass is 0.2 g, and space velocity is 6000 mL [g.sub.cat.sup.-1] [h.sup.-1]. However, the selectivity of propylene is only 63.33% and 0.25% in the propane dehydrogenation or C[O.sub.2] hydrogenation reaction, respectively. The ZnIn/HZSM-5 catalyst showed a higher stability with only 0.80% conversion drop after three cycles. Key words: ZnIn/HZSM-5, coupling reaction, propane, C[O.sub.2], propylene. Nous avons prepare le catalyseur ZnIn/HZSM5 par la methode d'impregnation a l'humidite naissante, et nous en avons caracterise la structure par diffraction des rayons X (DRX), microscopie electronique a balayage (MEB), microscopie electronique en transmission (MET), reduction en temperature programmee sous hydrogene ([H.sub.2]TPR), desorption thermo-programmee de l'ammoniac (N[H.sub.3]TPD), spectroscopie de photoelectrons X (XPS), thermogravimetrie (TG) et analyse d'adsorption-desorption d'azote. Nous avons ensuite etudie ce catalyseur dans la reaction de couplage du propane avec le C[O.sub.2] pour former le propylene. Nous avons observe que l'ajout d'especes de Zn favorise d'une part la dispersion de l'In2O3 dans la zeolithe HZSM5--un facteur important dans la formation du propene--et d'autre part la distribution de l'acidite dans le catalyseur In/HZSM5, ce qui ameliore de facon significative de l'activite catalytique de ce dernier. Le couplage du propane avec le C[O.sub.2] sur le catalyseur ZnIn/HZSM5 offre une selectivite pour le propylene de 68,21% lorsque le temps de reaction est de 2 h, la temperature de reaction de 580 [degrees]C, la pression de reaction de 0,3 MPa, le rapport des reactifs [C.sub.3][H.sub.6]:C[O.sub.2]:[N.sub.2] de 1:4:5, le poids du catalyseur de 0,2 g et la vitesse spatiale de 6000 mL [g.sub.cat-1] [h.sup.-1]. Toutefois, la selectivite pour le propylene n'est que de 63,33% pour la reaction de deshydrogenation du propane et de 0,25% pour la reaction d'hydrogenation du C[O.sub.2]. Le catalyseur ZnIn/HZSM5 a montre une stabilite superieure, la baisse de conversion etant de seulement 0,80% apres trois cycles. [Traduit par la Redaction] Mots-cles: ZnIn/HZSM-5, reaction de couplage, propane, C[O.sub.2], propylene., 1. Introduction Emissions of carbon dioxide have continuously increased over the past few decades, mainly from the combustion of natural gas, coal, and petroleum. (1) The increased concentration of C[O.sub.2] [...]

Bacteria can form biofilms in natural and clinical environments on both biotic and abiotic surfaces. The bacterial aggregates embedded in biofilms are formed by their own produced extracellular matrix. Staphylococcus aureus (S. aureus) is one of the most common pathogens of biofilm infections. The formation of biofilm can protect bacteria from being attacked by the host immune system and antibiotics and thus bacteria can be persistent against external challenges. Therefore, clinical treatments for biofilm infections are currently encountering difficulty. To address this critical challenge, a new and effective treatment method needs to be developed. A comprehensive understanding of bacterial biofilm formation and regulation mechanisms may provide meaningful insights against antibiotic resistance due to bacterial biofilms. In this review, we discuss an overview of S. aureus biofilms including the formation process, structural and functional properties of biofilm matrix, and the mechanism regulating biofilm formation. [ABSTRACT FROM AUTHOR]

Chlamydia trachomatis (CT) infection is the most prevalent sexually transmitted bacterial disease worldwide. However, unlike that in female infertility, the role of CT infection in male infertility remains controversial. The objective of this retrospective study was to explore the impacts of CT infection in the genital tract on sperm quality, sperm acrosin activity, antisperm antibody levels, and inflammation in a large cohort of infertile males in China. A total of 7154 semen samples were collected from infertile male subjects, 416 of whom were CT positive (CT+ group) and 6738 of whom were CT negative (CT− group), in our hospital between January 2016 and December 2018. Routine semen parameters (semen volume, pH, sperm concentration, viability, motility, morphology, etc.), granulocyte elastase levels, antisperm antibody levels, and sperm acrosin activity were compared between the CT+ and CT− groups. Our results showed that CT infection was significantly correlated with an abnormally low semen volume, as well as an increased white blood cell count and granulocyte elastase level (all P < 0.05) in the semen of infertile males; other routine semen parameters were not negatively impacted. The antisperm antibody level and sperm acrosin activity were not affected by CT infection. These findings suggested that CT infection might contribute to inflammation and hypospermia but does not impair sperm viability, motility morphology, and acrosin activity or generate antisperm antibodies in the infertile males of China. [ABSTRACT FROM AUTHOR]

Propane dehydrogenation to propene is an endothermic reaction and CO2 hydrogenation to light olefins is an exothermic reaction. Using the CO2 hydrogenation reaction to consume the hydrogen from the propane dehydrogenation reaction, which is more favorable to propylene formation. A new method for coupling propane and CO2 to propylene is presented. The V–Fe modified KIT-6 was prepared by the ultrasonic-assisted impregnation method and used for coupling reaction of propane with CO2 to propylene. Exploring the relationship between catalytic properties and physicochemical characteristics through several characterization methods. As the appropriate amounts of V and Fe species were introduced into the framework of KIT-6, V–Fe modified KIT-6 performed large specific surface area, a highly ordered mesoporous structure and highly dispersed V and Fe active sites. The catalysis performance of V–Fe modified KIT-6 zeolites for production of propylene by propane dehydrogenation, CO2 hydrogenation and coupling reaction of C3H8 with CO2 was compared. Under the conditions of C3H8/CO2/N2 = 1:4:5, total flow rate = 20 mL/min, the temperature at 580 °C, the reaction pressure at 0.1 MPa, V/Fe molar ratio = 2 and the catalyst mass of 0.2 g, the propane conversion, propylene selectivity and yield are 37.8%, 87.0% and 32.9%, respectively. [ABSTRACT FROM AUTHOR]

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Abstract: A series of novel red‐emitting Ca8ZnLa1−xEux(PO4)7 phosphors were successfully synthesized using the high‐temperature solid‐state reaction method. The crystal structure, photoluminescence spectra, thermal stability, and quantum efficiency of the phosphors were investigated as a function of Eu3+ concentration. Detailed analysis of their structural properties revealed that all the phosphors could be assigned as whitlockite‐type β‐Ca3(PO4)2 structures. Both the PL emission spectra and decay curves suggest that emission intensity is largely dependent on Eu3+ concentration, with no quenching as the Eu3+ concentration approaches 100%. A dominant red emission band centered at 611 nm indicates that Eu3+ occupies a low symmetry sites within the Ca8ZnLa(PO4)7 host lattice, which was confirm by Judd‐Ofelt theory. Ca8ZnLa1−xEux(PO4)7 phosphors exhibited good color coordinates (0.6516, 0.3480), high color purity (~96.3%), and high quantum efficiency (~78%). Temperature‐dependent emission spectra showed that the phosphors possessed good thermal stability. A white light‐emitting diode (LED) device were fabricated by integrating a mixture of obtained phosphors, commercial green‐emitting and blue‐emitting phosphors into a near‐ultraviolet LED chip. The fabricated white LED device emits glaring white light with high color rendering index (83.9) and proper correlated color temperature (5570 K). These results demonstrate that the Ca8ZnLa1−xEux(PO4)7 phosphors are a promising candidate for solid‐state lighting. [ABSTRACT FROM AUTHOR]

Abstract: The solubility of carbon dioxide (CO2) and hydrogen sulfide (H2S) in basic aqueous electrolyte solutions is determined by a combined phase and reaction equilibrium. A cubic equation of state is applied to model the vapor-liquid equilibria of these reacting systems. The Peng-Robinson equation of state with Wong-Sandler mixing rules is combined with an extended UNIQUAC model for electrolytes where ion-specific interactions are determined from a Debye-Hückel term. The thermodynamic model is parameterized for aqueous systems containing carbon dioxide and hydrogen sulfide along with water and potassium carbonate solutions at high pressure. The UNIQUAC binary interaction parameters are estimated by minimizing deviations in the liquid phase composition of the model with respect to the experimental data. The data is taken from literature and is supplemented by own experimental work conducted as part of this study. [Copyright &y& Elsevier]

Abstract: The role of various carboxylic acids (substituted/unsubstituted acetic, benzoic and salicylic acids) with various electron donating and/or withdrawing substituents on the Na2WO4/H2WO4-catalysed, biphasic epoxidations of cyclooctene and 1-octene, using H2O2 as terminal oxidant has been investigated. The presence of the different acids in catalytic amounts widely affects the catalytic activity of the above system depending on the nature of their substituents. The results obtained have been discussed in the light of the stereo/electronic effects of these substituents. It has been observed that the added substituted/unsubstituted acetic and benzoic acids generally enhance the rate of the epoxidation while salicylic acids significantly decrease the catalyst activity, under the same conditions, most likely due to the additional deactivating hydroxy moiety. [Copyright &y& Elsevier]