Studies on the Synthesis of Penazetidine A, an Alkaloid Inhibitor of Protein Kinase C

A convergent asymmetric synthesis of (2S, 3R, 4S, 12'R)-3-hydroxy-2-hydroxymethyl- 4-(12' -methyloctadecyl)-N-(p-tolylsulfonyl)-azetidine, a key precursor of penazetidine A, has been achieved by starting from divinylcarbinol.

One-step preparation of a novel graphitic biochar/Cu^(0)/Fe_(3)O_(4) composite using CO_(2)-ambiance pyrolysis to activate peroxydisulfate for dye degradation

Herein,a one-step co-pyrolysis protocol was adopted for the first time to prepare a novel pyrogenic carbon-Cu^(0)/Fe_(3)O_(4)heteroatoms (FCBC) in CO_(2)ambiance to discern the roles of each component in PDS activation.During co-pyrolysis,CO_(2)catalyzed formation of reducing gases by biomass which facilitated reductive transformation of Fe^(3+)and Cu^(2+)to Cu^(0)and Fe_(3)O_(4),respectively.According to the analysis,the resulting metal (oxide) catalyzed graphitization of biocharand decomposition of volatile substances resulting in an unprecedented surface area (1240 m^(2)/g).The resulting FCBC showed greater structural defects and less electrical impedance.Batch experiments indicated that Rhodamine B (RhB) degradation by FCBC (100%) was superior to Fe_(3)O_(4)(50%) and Cu^(0)/Fe_(3)O_(4)(76.4%) in persulfate (PDS) system,which maintained reasonable efficiency (75.6%-63.6%) within three cycles.The reactive oxygen species (ROS) associated with RhB degradation was identified by an electron paramagnetic resonance and confirmed by scavenging experiments.RhB degradation invoked both(sulfate and dominantly hydroxyl) radical and non-radical (singlet oxygen,^(1)O_(2)) pathways.Regarding FCBC,Cu^(0)can continuously react with Fe^(3+)in Fe_(3)O_(4)to generate larger quantities of Fe^(2+),and both Cu^(0)and Fe^(2+)activated PDS to yield sulfate radicals which was quickly converted to hydroxyl radical.Besides,Cu^(0)/Cu^(2+)could complex with PDS to form a metastable complex,which particularly contributed to1O_(2)generation.These cascade reactions by FCBC were reinforced by carbonyl group of biochar and favorable electron transfer ability.This work highlighted a new approach to prepare a magnetic and environment-benign heterogonous catalyst to remove organic pollutants in water.

Nitrogen removal and simultaneous nitrification and denitrification in a fluidized bed step-feed process

For urban wastewater treatment,we conducted a novel four-stage step-feed wastewater treatment system combined with a fluidized bed laboratory experiment to investigate chemical oxygen demand（COD）,NH4＋-N,and total nitrogen（TN） removal performance.The removal rates of COD,NH4＋-N and TN were 88.2%,95.7%,and 86.4% with e？uent concentrations of COD,NH4＋-N and TN less than 50,8,and 10 mg/L,respectively.Biomass and bacterial activities were also measured,with results showing more nitrobacteria in the activated sludge than in the biofilm;however,bacterial activity of the biofilm biomass and the activated sludge were similar.Nitrogen concentrations during the process were also detected,with simultaneous nitrification and denitrification found to be obvious.

Environmental Efficiency and the Optimal Size of Chinese Cities

The spatial distribution of population and economic activities has tmportant tmpacts onboth economic growth and the environment. This paper uses a slack-based measure toestimate the total factor environmental efficiency （TFEE） of 286 Chinese prefectural-and-above cities for the period 2002-2013. In particular, the relationship between citysize and TFEE is investigated. The findings also show an inverted U-shaped relationshipbetween TFEE and city size, which implies an optimal city size of 16.68 million residentsin China. According to this estimate, most Chinese cities may be undersized due to themigration restrictions of the hukou registration system and, hence, suffer from greatenvironmental efficiency losses. The estimated low average TFEE value of Chinese citiesalso suggests the large potential for efficiency improvement. Thus, government policiesshould focus on relaxing migration restrictions and encouraging the development oflarge cities.

Computation on Sentence Semantic Distance for Novelty Detection

Novelty detection is to retrieve new information and filter redundancy fromgiven sentences that are relevant to a specific topic. In TREC2003, the authors tried an approach tonovelty detection with semantic distance computation. The motivation is to expand a sentence byintroducing semantic information. Computation on semantic distance between sentences incorporatesWordNet with statistical information. The novelty detection is treated as a binary classificationproblem: new sentence or not. The feature vector, used in the vector space model for classification,consists of various factors, including the semantic distance from the sentence to the topic and thedistance from the sentence to the previous relevant context occurring before it. New sentences arethen detected with Winnow and support vector machine classifiers, respectively. Several experimentsare conducted to survey the relationship between different factors and performance. It is provedthat semantic computation is promising in novelty detection. The ratio of new sentence size torelevant size is further studied given different relevant document sizes. It is found that the ratioreduced with a certain speed (about 0.86). Then another group of experiments is performedsupervised with the ratio. It is demonstrated that the ratio is helpful to improve the noveltydetection performance.

Distribution and molecular variability of four tobacco viruses in China

Dear Editor,Plant viruses cause great economic losses to tobacco production(Dai et al.,2012).Many types of viruses have been reported to infect tobacco plants,including Tobacco mosaic virus(TMV)(Chen et al.,2014),Cucumber mosaic virus(CMV)(Dai et al.,2012),Tobacco

Epitaxial growth of highly strained antimonene on Ag（111）

The synthesis of antimonene, which is a promising group-V 2D material for both fundamental studies and technological applications, remains highly challenging. Thus far, it has been synthesized only by exfoliation or growth on a few substrates. In this study, we show that thin layers of antimonene can be grown on Ag（111） by molecular beam epitaxy. High-resolution scanning tunneling microscopy combined with theoretical calculations revealed that the submonolayer Sb deposited on a Ag（111） surface forms a layer of AgSb2 surface alloy upon annealing. Further deposition of Sb on the AgSb2 surface alloy causes an epitaxial layer of Sb to form, which is identified as antimonene with a buckled honeycomb structure. More interestingly, the lattice constant of the epitaxial antimonene （5 /-） is much larger than that of freestanding antimonene, indicating a high tensile strain of more than 20%. This kind of large strain is expected to make the antimonene a highly promising candidate for room- temperature quantum spin Hall material.

Anthology, Criticism, and Canonization An In-Depth Analysis of Ancient Chinese Literary Anthologies

The literary anthology is one of the key categories in ancient Chinese literary theory and criticism. Theoretically, anthology criticism focuses on three main areas： the preface and postscript, the annotation of the anthology, and the works selected for inclusion in the anthology. Anthology criticism is unique in its methodological synergy, including the direct and indirect communication of literary judgments and the amalgamation of critical theory and practice. This paper argues that the anthology as a form of literary criticism possesses great theoretical value; it sheds light on the development of literary concepts and forms, as well as suggesting the nature of literary transmission. Therefore, the literary anthology plays a key role in the canonization of Chinese literature.