Search

Catalytic upcycling of polyolefins into high‐value chemicals represents the direction in end‐of‐life plastics valorization, but poses great challenges. Here, we report the synthesis of a tandem porous catalyst via a micelle cascade assembly strategy for selectively catalytic cracking of polyethylene into olefins at a low temperature. A hierarchically porous silica layer from mesopore to macropore is constructed on the surface of microporous ZSM‐5 nanosheets through cascade assembly of dynamic micelles. The outer macropore arrays can adsorb bulky polyolefins quickly by the capillary and hydrophobic effects, enhancing the diffusion and access to active sites. The middle mesopores present a nanoconfinement space, pre‐cracking polyolefins into intermediates by weak acid sites, which then transport into zeolites micropores for further cracking by strong Brønsted acid sites. The hierarchically porous and acidic structures, mimicking biomimetic protease catalytic clefts, ideally match the tandem cracking steps of polyolefins, thus suppressing coke formation and facilitating product escape. As a result, light hydrocarbons (C1‐C7) are produced with a yield of 443 mmol gZSM‐5−1, where 74.3 % of them are C3‐C6 olefins, much superior to ZSM‐5 and porous silica catalysts. This tandem porous catalyst exemplifies a superstructure design of catalytic cracking catalysts for industrial and economical upcycling of plastic wastes. [ABSTRACT FROM AUTHOR]

Background: To explore the pathogen distribution in Chinese females with vaginitis. Methods: This retrospective study included Chinese females with vaginitis admitted at the outpatient department of the Gynecology Clinic of the Second Affiliated Hospital of Kunming Medical University between January 2013 and June 2013. Data on the vaginal pathogens and inflammation were analyzed. Results: The vaginal secretions from 15,601 gynecologic outpatients were abnormal, including 8547 (54.78%) with vaginal infection and 7054 (45.22%) without. In patients with vaginal infections, a single infection was observed in 69.72% (5959/8547) of them, and mixed infection was observed in 30.28% (2588/8547). The differences in age and inflammation grade between the infection and no-infection groups were statistically significant (all P < 0.001). In addition, multiple types of vaginitis could be diagnosed in patients with mixed infections. Conclusions: About half of the Chinese women with abnormal vaginal secretions are positive for pathogens in the study period. Patients' age and inflammation grade are associated with co-infection. From the public health perspective, this study suggests that the importance of vaginal hygiene should be enforced in Chinese women. [ABSTRACT FROM AUTHOR]

Biomass conversion and biorefineries provide a feasible and novel way to release the increasingly serious energy crisis and environmental deterioration. 2,5-furandicarboxylic acid (FDCA) has received increasing attention as a significant platform chemical that can potentially replace petroleum-derived terephthalate acid (TPA) and produce green polymers such as polyethylene-2,5-furandicarboxylate (PEF). In recent years, the blooming development of HMF electrochemical oxidation (HMF-EOR) has given a new birth to the traditional aerobic oxidation, which only needs non-noble metal-based electrocatalysts to convert HMF into FDCA under appropriate potential and ambient temperature. Cathodic H2 evolution reaction or biomass reduction reaction, coupled with anodic HMF oxidation, can also provide more value for HMF-EOR. In this review, most recently reported studies on the electrocatalytic synthesis of FDCA from HMF are introduced, including the structure and electrochemical performance of catalysts, reaction mechanism, optimization of the reaction conditions, and characterization methods. Electrocatalysts without noble metals are classified according to their composition, which has great effects on their catalytic activity. Furthermore, challenges and suggestions for HMF-EOR are provided in the end. It is anticipated that this review could promote scientists to develop effective electrocatalysts for the economical and environment-friendly synthesis of FDCA in industrial applications. [ABSTRACT FROM AUTHOR]

Moniezia expansa (M. expansa) parasitizes the small intestine of sheep and causes inhibited growth and development or even death. Being globally distributed, it causes considerable economic losses to the animal husbandry industry. Here, using Illumina, PacBio and BioNano techniques, we obtain a high-quality genome assembly of M. expansa , which has a total length of 142 Mb, a scaffold N50 length of 7.27 Mb and 8,104 coding genes. M. expansa has a very high body fat content and a specific type of fatty acid metabolism. It cannot synthesize any lipids due to the loss of some key genes involved in fatty acid synthesis, and it may can metabolize most lipids via the relatively complete fatty acid β-oxidation pathway. The M. expansa genome encodes multiple lipid transporters and lipid binding proteins that enable the utilization of lipids in the host intestinal fluid. Although many of its systems are degraded (with the loss of homeobox genes), its reproductive system is well developed. PL10, AGO, Nanos and Pumilio compose a reproductive stem cell regulatory network. The results suggest that the high body lipid content of M. expansa provides an energy source supporting the high fecundity of this parasite. Our study provides insight into host interaction, adaptation, nutrient acquisition, strobilization, and reproduction in this parasite and this is also the first genome published in Anoplocephalidae. [ABSTRACT FROM AUTHOR]

To construct a green chemical synthesis system for a better future of human beings, the utilization of water as an oxygen source and electricity as the driving force for the oxygenation of biomass valorization is of great significance and essential. Here, we first investigated the possibility for 5-hydroxymethylfurfural (HMF) electrooxidation into 2,5-furandicarboxylic acid (FDCA) by Ni-based two-dimensional metal–organic frameworks (2D MOFs) as electrocatalysts. FDCA is a desirable alternative to fossil-based terephthalic acids for the production of environmentally friendly polymers. The as-prepared Co-doped 2D MOFs NiCoBDC (Ni2+, BDC = terephthalic acid) have a high FDCA yield of 99%, an excellent yield rate of 20.1 μmol cm−2 h−1 and a faradaic efficiency of 78.8% at 1.55 V vs. RHE, as performed in an electrolyte at pH 13, where the degradation of HMF was ignored. Benefitting from the accessible pores of HMF molecules, abundant exposed active sites and coupling effects between Ni and Co atoms, 2D NiCo-MOFs realized a high catalytic activity and a robust electrochemical durability. This work demonstrates 2D MOFs as promising electrocatalysts for highly efficient biomass valorization because of their porosity and rich active sites. [ABSTRACT FROM AUTHOR]

Owing to the combination of intriguing activity and conductivity, hybrid compositions of layered double hydroxides (LDHs) and carbon-based materials have been extensively and widely applied to evolve oxygen gas during water splitting. Here, a facile in situ nucleation strategy was used to construct ultrafine NiFe-LDH nanosheets monodispersed on a carbon black (CB) substrate. Notably, this work displayed the interfacial impact of combining CB with NiFe-LDHs on electrocatalyst activation. Interestingly, the optimized NiFe-LDHs/CB composite displays a fast activation rate and excellent water oxidation performance on a glassy-carbon electrode (an overpotential of 226 mV at 10 mA cm−2; a Tafel slope of 57 mV dec−1). This is due to the high active area, low impedance and ultra-high active metal atom utilization rate, accelerating charge transfer at the interface during the activation process. More importantly, this work highlights the interfacial charge transfer effect during the activation process and supplies clues for designing electrocatalysts. [ABSTRACT FROM AUTHOR]