Recent Advances in Ynenamine Chemistry.

Enamines are formed by reacting a carbonyl compound with an amine under dehydration conditions. A vast array of transformations has been achieved via preformed enamine chemistry. Recently, by introducing conjugating double bonds to the enamine functionality, dienamines, and trienamines have propelled the discovery of several previously unattainable remote-site functionalization reactions of carbonyl compounds. Comparatively, alkyne-conjugating enamine analogues have recently shown high potential in multifunctionalization reactions while remaining underexplored. In this account, we systematically summarized and discussed recent advances in synthetic transformations based on ynenamine-containing compounds.

Study on the thawing characteristics of beef in ultrasound combined with plasma-activated water.

The effects of deionized water thawing (DT), plasma-activated water thawing (PT), ultrasound (150 W, 40 kHz) combined with deionized water thawing (UDT), and ultrasound combined with plasma-activated water thawing (UPT) on the thawing characteristics and the physicochemical properties of the beef were investigated. The results showed that the UPT group had a faster thawing rate (38 % higher compared to the PT group) and good bactericidal ability (75 % higher compared to the UDT group), and had no adverse effect on the color and pH value of the beef. Plasma-activated water (PAW) can maintain the stability of the beef fiber, improve the water holding capacity (WHC), inhibit lipid oxidation, and reduce the loss of soluble substances such as protein. Therefore, UPT thawing is a promising meat thawing technology, which provides practical guidance and methods for the wide application of UPT in the field of meat thawing.

[Effects of arbuscular mycorrhizal fungi on terpenoids in Isodon adenantha].

OBJECTIVE: To observe the effects of Arbuscular Mycorrhizal (AM) fungi on terpenoids in Isodon adenantha. METHODS: Three different treated plant groups were divided as followings: indoor inoculation with AM fungi, non-inoculation with AM fungi, and outdoor natural growth, the effects of AM fungi on the major terpenoids in Isodon adenantha were evaluated. RESULTS: AM fungi had little influence on the content of terpenoids in underground part of Isodon adenantha, but they showed great impact on the content of terpenoids in the aerial part of the plant. CONCLUSION: The content of terpenoids in the aerial part of Isodon adenantha is positively correlated with AM fungi.

Simple Way to Fabricate Emissive Boron-Containing Covalent Organic Frameworks.

Highly fluorescent covalent organic frameworks (COFs) are rarely obtained because of the π-π stacked layers with aggregation-caused quenching behavior. Unarguably, highly fluorescent COFs with tunable emission colors are even more rarely achieved. Herein, a general strategy to modify the classical COF material (named COF-1) by different fluorescent molecules via N → B interaction was developed. In this method, the boron-containing COF-1 acted as a porous and crystalline matrix as well as a reaction partner of Lewis acid; after interacting with fluorescent molecules with the anchoring group of pyridine (Lewis base), COF-1 takes a gorgeous transfiguration from a non-emissive powder into a highly fluorescent COF material with tunable emission colors. This disclosed method endowed the typical COFs with new emissive life and is speculated with the general research concept for all boron-containing COFs. Benefiting from the prominent fluorescent emission in the aggregation state, sensitive probes toward amines are achieved.

Influence of electrohydrodynamics on the drying characteristics and physicochemical properties of garlic.

Electrohydrodynamic (EHD) drying, natural air drying (AD) and hot air drying (HAD) were used to comprehensively study the drying characteristics and physicochemical properties of garlic, and low-field nuclear magnetic resonance (NMR), infrared spectroscopy, scanning electron microscopy and other technologies were used as detection methods. In terms of drying characteristics, HAD has the largest effective diffusion coefficient of moisture and the shortest average drying time. EHD-treated garlic slices had the most attractive color, the highest rehydration rate, the most stable cell structure, the highest content of active ingredients, and the most stable protein secondary structure. Therefore, electrohydrodynamic drying is a promising garlic slice drying technology and provides an effective method for the large-scale production of high-quality garlic.

Influence of electrohydrodynamics on the drying characteristics and volatile components of iron stick yam.

The drying characteristics, rehydration capacity, color, infrared spectra and volatile components of iron stick yam slices were investigated under different alternating current (AC) voltages (13, 17, 21 kV), hot air drying (HAD) (60 °C) and natural drying (AD) by electrohydrodynamic (EHD) drying and HAD experimental devices. The results showed that slices of iron stick yam dried the quickest with HAD, which also had the fastest drying rate; while drying the slices of iron stick yam with EHD led to a better rehydration capacity, higher brightness L* and whiteness, a more stable protein secondary structure, and a greater variety and content of volatile components compared with AD and HAD. These finding indicated that EHD is a more promising method for drying iron stick yam.

Analysis of the Urban Land Use Efficiency in the New-Type Urbanization Process of China's Yangtze River Economic Belt.

The accelerated urbanization process in China has caused a shift in the urban land use structure. The Chinese government has issued 'the National New-type Urbanization Plan' focusing on the rational use of resources, which is of great significance for the intensification and sustainability of land use. In promoting the construction of the new-type urbanization (N-TU), enhancing the urban land use efficiency (ULUE) is crucial to regional coordinated development. This study uses panel data from 2011 to 2020 for 11 provinces (cities) in the Yangtze River Economic Belt (YREB) and adopts the super efficiency (SE) slacks-based measure (SBM) model with undesirable outputs and the entropy weight method to calculate the ULUE and N-TU levels. The study uses the System generalized method of moment (Sys-GMM) to study the N-TU's impact on the ULUE empirically. The results indicate: (i) the overall trend of new-type urbanization level is gradually increasing and has the characteristics of uneven spatial distribution between provinces. (ii) The ULUE shows a fluctuating upward trend during the studied period. (iii) The N-TU and its subsystems have significant positive effects on the ULUE. Overall, this study aims to explore the relationship between the N-TU and ULUE enriching the theoretical analysis and empirical research in related fields, thus helping decision makers in the assessment and design of policy recommendations.

A Cost-Effective Way to Produce Gram-Scale 18O-Labeled Aromatic Aldehydes.

Obtaining 18O-labeled organic substances is of great research importance and also an extremely challenging work. In this work, depending on the reversed Knoevenagel reaction, 18O-labeled aromatic aldehydes (3a-3x) are successfully obtained with high total yields (52-72%) and sufficient 18O abundance (90.90-96.09%).

Hypochlorite Detection by Fluorescent Sensors Bearing Long Alkyl Chains: The Role of Chain Length in Sensing Properties.

Three pyridinium derivatives bearing alkyl chains of different lengths (C1, C8, and C18) that show aggregation-enhanced emission were synthesized. These compounds can be used to detect ClO- ion as the reaction releases the fluorescent core with an increase in emission intensity and change in absorption wavelength. The lowest detection limit of TPA-Pyr-18C was 6.04 µM. The length of the alkyl chain and resulting lipophilicity allowed the targeting of different subcellular structures. TPA-Pyr-18C could be used for staining yolk lipids in zebrafish.

Functional Copolymers Married with Lanthanide(III) Ions: A Win-Win Pathway to Fabricate Rare Earth Fluorescent Materials with Multiple Applications.

Lanthanide(III)-based luminescent materials have attracted great research interests due to their unique optical, electronic, and chemical characteristics. Up to now, how to extend these materials into large, broad application fields is still a great challenging task. In this contribution, we are intended to present a simple but facile strategy to enhance the luminescence from lanthanide ions and impart lanthanide(III)-based luminescent materials with more applicable properties, leading to meet the requirements from different purposes, such as being used as highly emissive powders, hydrogels, films, and sensitive probes under external stimuli. Herein, a water soluble, blue color emissive, temperature sensitive, and film-processable copolymer (Poly-ligand) was designed and synthesized. Upon complexing with Eu3+ and Tb3+ ions, the red color-emitting Poly-ligand-Eu and green color-emitting Poly-ligand-Tb were produced. After finely tuning the ratios between them, a standard white color emitting Poly-ligand-Eu1:Tb4 (CIE = 0.33 and 0.33) was obtained. Furthermore, the resulted materials not only possessed the emissive luminescent property but also inherited functions from the copolymer of Poly-ligand. Thus, these lanthanide(III)-based materials were used for fingerprint imaging, luminescent soft matters formation, colorful organic light-emitting diode device fabrication, and acid/alkali vapors detection.