Visible-Light-Mediated Deacylated Alkynylation of Unstrained Ketone.

Deconstructive alkynylation of an unstrained ketone catalyzed by an organic photocatalyst under blue light irradiation is reported for the first time. A broad substrate scope with up to 63 examples, excellent functional group tolerance, and gram scale reaction demonstrated the practicality of this novel alkynylation method. The dihydroquinazolinone derivative of trifluoroacetophenone had been proved to have potential as a novel trifluoromethylation reagent after working well for the trifluoromethylation reaction with various alkynyl bromides.

The impact of environment on college students' entrepreneurial intention based on the mediating effect of personality traits.

Introduction: The entrepreneurship rate of Chinese college students is relatively low. This study investigates the environment factors that influence college students' entrepreneurial intention as mediated by personality traits. Methods: According to the entrepreneurial ecosystem theory, a hierarchical model of the environment factors was established which included three layers: personality traits as the micro system, family and education as the meso system, and social and policy support as the macro system. The structural equation model of the environment factors was constructed to reveal the significant influence path of various factors and the mediating role of personality traits. Data were collected from 436 undergraduate students in Henan Province, China. Results: Findings indicate that family, education, social, and policy factors have no significant direct influence on entrepreneurial intention. However, personality traits significantly influence entrepreneurial intention and mediate the effects of various factors on entrepreneurial intention. Discussion: Suggestions such as improving college students' entrepreneurial practice and promoting college students' proactive personalities are also put forward.

Insights into ion imprinted membrane with a delayed permeation mechanism for enhancing Cd2+ selective separation.

Ion imprinted polymers exhibit great potential in ion separation from wastewater. However, the difficulty of ion separation by membrane is proverbial, which severely restricts the application of membrane in metal resource recovery from industrial wastewater. Herein, a rational molecular-level design approaches for membrane fabrication was developed to modify a layer of ion imprinted polymer onto the PVDF membrane. Batch rebind and permeation experiments suggest that specific host-guest binding sites had been fabricated along the membrane pore in ion imprinted membranes (IIM). A higher monomer dose leads to a higher rejection of Cd2+, and the more bind sites in IIM. The binding of IIM to Cd2+ was 1.84 times that of non-ion imprinted membranes (NIM). Permselectivity factors (γ) of IIM are larger than 5.39 in mixture ions solutions. Chemical characterization and density functional theory (DFT) calculation reveal that the Cd2+ recognition sites of functional groups are C-S and C˭S. Cd2+ mass transport in IIM suggest that the imprint effects provide a binding force that would delay Cd2+ to permeate through IIM, so as to selectively separate Cd2+ with other ions. The imprint effects may enlighten a novel molecular-level design approaches for membrane fabrication to enhance the selectivity of ion-ion.

Purification and characterization of a thaumatin-like protein-1 with polyphenol oxidase activity found in Prunus mume.

Thaumatin-like protein-1 (TLP-1), a protein displaying high polyphenol oxidase (PPO) action and a member of the pathogenesis-related (PR) protein family, has a considerable influence on the enzymatic browning of Prunus mume (Chinese plum). In this assay, TLP-1 was identified and extracted from Prunus mume to investigate the protein's properties and better understand its contribution to the fruit's browning during storage or processing. The extracted TLP-1 was purified to apparent homogeneity using a procedure involving citrate phosphate buffer solution (CPBS) extraction, (NH4)2SO4 precipitation, dialysis in a cellulose bag, and ion exchange chromatography using a DEAE Sepharose Fast Flow column, while a Sephadex G-75 column was employed to facilitate gel filtration chromatography. Moreover, the enzyme was characterized in terms of its optimal pH and stability, isoelectric point (pI), molecular weight, optimal temperature and stability, enzyme kinetic parameters and substrate specificity, as well as inhibitor stability. This study indicated that the pI and molecular weight of TLP-1 was approximately 4.4 and 28 kDa, respectively, while 30 °C and 7.5 represented the respective optimal temperature and pH level for PPO catalysis. TLP-1 showed high affinity to catechol and pyrogallol, with K m values of 24.40 mM and 26.23 mM, respectively. Sodium bisulfite significantly inhibited TLP-1 activity. These findings on the properties of TLP-1 can contribute significantly to the search for ways to minimize the losses caused by fruit browning during the storage and processing of Prunus mume.

Evaluating the adsorptivity of organo-functionalized silica nanoparticles towards heavy metals: Quantitative comparison and mechanistic insight.

Organo-functionalized SiO2 nanoparticles are regarded as promising adsorbents for capture of heavy metals. However, actual adsorptivity of a specific functional group onto SiO2 surface is unclear, thus extending a debate on which type of organic group possesses a better affinity toward heavy metals. Herein, surface functionalization of SiO2 with different groups (i.e., -EDTA (ethylenediamine triacetic acid), -COOH, -SO3H, -SH and -NH2) were achieved by a facile silylating reaction. Batch experiments indicated that adsorption capacity of SiO2 was remarkably improved by surface functionalization. Quantitative analysis manifested that one mole of EDTA grafted onto SiO2 surface can adsorb 1.51 mol of Pb(II) ions, which was 7.7, 17.1, 28.4 and 50.2-fold larger than those of COOH-, SO3H-, SH- and NH2-functionalized SiO2, respectively. This is first time to evaluate adsorptivity of functionalized SiO2 on the basis of per effective functional group, which may repair deficiency of conventional assessment method that calculated on the basis of per unit mass. Further, adsorption mechanism of these functionalized SiO2 were identified and uncovered by experimental and theoretical studies. This work not only develops an efficient adsorbent for heavy metal remediation but also provides a valuable insight for evaluation and design of novel SiO2-based materials.

Effects of Controlled Atmosphere on the Storage Quality and Aroma Compounds of Lemon Fruits Using the Designed Automatic Control Apparatus.

'Eureka' lemon fruits were stored under four controlled atmosphere- (CA-) combinations at 8°C for 20 days to investigate the effects on weight loss (WL), total soluble solids (TSS), titratable acidity (TA), vitamin C (VC), total phenolic content (TPC), sodium carbonate-soluble pectin (SSP), malondialdehyde (MDA), and volatile compounds. Results showed that the contents of TSS, TA, VC, and SSP in the stored fruits reduced during the storage period, while the WL and MDA increased. Fruit stored under CA2-combination (6 % O2+8 % CO2) showed the lower contents of WL and MDA and the higher content of TSS, TA, TPC, and VC than that of other treated fruits. The main volatile compounds present in the lemons were terpenoids, aldehydes, alcohols, and esters. In addition, both the terpenoid and aldehyde content are substantially higher in lemons exposed to CA2 conditions. In contrast, the alcohols and esters displayed elevated levels in the regular air (RA) stored fruit. In conclusion, CA with the suitable conditions proves to be better than RA as a storage regimen to keep the quality of lemons. These results indicated that the application of 6% O2+8% CO2 CA conditions could maintain the quality of 'Eureka' lemon fruit during the storage time of 20 days and should be the optimal storage environment for postharvest Eureka lemons.

How do housing prices affect consumption in China? New evidence from a continuous wavelet analysis.

In this paper, we revisit the relationship between housing prices and consumption in China by using a continuous wavelet analysis. This method provides an insight into the dynamic nexus in both time and frequency domains. In general, Empirical results show that there is a positive relationship between the two series in China, although it varies across time and frequencies. First, we find that disposable income is the core factor which affects both consumption and housing prices in China. Second, housing prices have a weak wealth effect on consumption in most time. High housing ownership and proportion of housing asset in the total household asset lead to a wealth effect of housing prices on consumption. Third, in the long term, there is a significant wealth effect of housing prices on consumption, but it weakens after 2008, which implies that excessively high housing prices in recent years have partially constrained residents' consumption. These findings have important implications for seeking housing market regulation and expanding domestic consumption decisions.