Latest ArticlesA millimeter scale butterfly-shaped reactor was proposed based on sizing-up strategy and fabricated via femtosecond laser engraving. An improvement of mixing performance and residence time distribution was realized by means of contraction and expansion of the reaction channel. The liquid holdup was greatly increased through connection of multiple mixing units. Structure optimization of the reactor was carried out by computational fluid dynamics simulation, from which the effect of reactor internals on mixing and the influence of parallel branching structure on heat transfer were discussed. The UV–vis absorption spectroscopy was used to determine the residence time distribution in the reactor, and characteristic parameters such as skewness and dimensionless variance were obtained. Further, a chained stagnant flow model was proposed to precisely describe the trailing phenomenon caused by fluid stagnation and laminar flow in small scale reactors, which enables a better fit for the experimental results of the asymmetric residence time distribution. In addition, the heat transfer performance of the reactor was investigated, and the overall heat transfer coefficient was 110–600 W m-2 K-1 in the flow rate range of 10–40 mL/min.
Nineteen diterpenoids, including saldigitin A (1) bearing an unprecedented 10-methylated 6/7/6 carbon ring system, two new icetexanes (2, 3), and two new nor-abietanes (5, 6) were characterized from the roots of Salvia digitaloides. Their structures were elucidated by the analysis of the spectroscopic data, X-ray crystallography, and TDDFT calculations of ECD spectra. The novel architecture of 1 should be biogenetically derived through the cleavage and re-cyclization of the B/C rings from the normal abietane skeleton. Biologically, 1–5 exhibited noticeable inhibitions on Cav3.1 low voltage-gated Ca2+ channel (LVGCC), with IC50 values in the range of 3.43–11.70 µmol/L. They are the first example of diterpenoids with 6/7/6 carbon rings system as Cav3.1 antagonists.
Stimuli-responsive macrocycles are of importance for synthetic chemistry and smart materials. In this manuscript, we report two novel organoborane cyclophanes, which were successfully synthesized by ruthenium-catalyzed olefin metathesis. They are composed of one/two boron-doped helicene π-skeletons and flexible alkyl chain linkers, thus representing a new kind of non-conjugated organoborane macrocycles. Their cyclic structures and photophysical properties, as well as Lewis acidity were theoretically and experimentally investigated. Notably, two enantiomers in one single crystal are observed for one organoborane cyclophane, owning to the presence of helical π-framework in its cyclic structure. Moreover, their Lewis acid-base adducts may dissociate in the excited state and thus display intriguing photo-responsive fluorescence properties, which can be further modulated by temperature. This study thus provides a novel design strategy for non-conjugated organoborane macrocycles, which may promote the development of stimuli-responsive macrocyclic materials with fascinating properties.
Control of self-assembly is significant to the preparation of supramolecular materials, but the control of hydration, responsiveness, dimension, catalysis of macrocyclic amphiphiles in an atom-economic manner is still a great challenge. The herein presented 527 Da low-molecular-weight macrocyclic amphiphile was fabricated by utilizing the selenium-containing crown ether as a hydrophobic motif together with guanidinium group as the hydrophilic moiety. The resulting benzo[21]crown-7 based macrocyclic amphiphile readily forms a redox-responsive solid nanoparticles in water, which can further interconnect into wrinkled pattern on-surface, as well as exhibits as a nanozyme for catalyzing disulfid bond formation. The present work highlights the great potential of guanidinium- and selenium-containing crown ethers for the control of functional assemblies.
Hypertension is the leading risk factor for death and disability, and hypertensive patients always need long-term oral antihypertensive drugs. Some bioactive peptides that extracted from animals or plants have shown excellent advantages on antihypertension. However, the oral delivery of these peptides is always failure on account of instability and poor absorption in the gastrointestinal tract. Herein, we developed a core-shell lipid-polymeric nanoparticle for oral delivery of a highly efficient antihypertensive peptide KY5 (KY5-CSs). KY5-CSs had a particle size of 216.7 ± 2.5 nm, with a narrow PDI of 0.07 ± 0.01. The zeta potential was −4.1 ± 0.1 mV. It exhibited good stability in 4 °C and possessed a controlled release behavior in gastrointestinal tract. The cellular uptake study proved that the lipid shell imparted unique capability of permeation across the mucus layer and internalization by Caco-2/HT-29 cells. In addition, KY5-CSs enhanced in situ intestinal absorption in SD rats. The pharmacokinetic studies and antihypertensive efficacy showed a superior oral absorption and antihypertensive effect of KY5-CSs than KY5-NPs. In conclusion, the core-shell lipid-polymeric nanoparticles will provide attractive potential for oral delivery of antihypertensive peptides.
Gel polymer electrolytes (GPEs) are considered to be one most promising alternative to liquid electrolytes due to their suitability for creating safe and durable solid-state lithium-metal batteries. However, the mechanical properties of GPEs usually deteriorate dramatically when polymer matrices are plasticized by a liquid electrolyte, which leads to significant loss of battery performance. Therefore, the long-term structural integrity and good mechanical strength are critical characteristics of GPEs designed for high-performance batteries. Here, an ecologically compatible cellulose-based GPE with a crosslinked structure is synthesized via a facile and effective thiol-ene click chemistry method. The prepared thiol-ene crosslinked GPE possesses enhanced mechanical strength (10.95 MPa) and rigid structure, which enabled us to fabricate LiFePO4|Li batteries with ultra-long cycling performance. The capacity retention of the crosslinked cellulose-based GPE can be up to 84% at 0.5 C, even after 350 cycles, which is considerably higher than that of non-crosslinked GPE for which rapid decline in capacity occurs after 200 cycles. In addition, a GPE preparation method described in this work compares favorably well with existing commercial electrolytes for lithium metal batteries.
Available online Iodinated X-ray contrast media (ICMs) are clinical drugs used to enhance the imaging effect. Triiodobenzene ring structures of ICMs lead to its extremely high chemical stability, biological inertness, which makes it difficult to be completely removed by traditional water treatment processes. Hence, considerable concentration of ICMs can be frequently detected in aquatic environment. Relying on the strong oxidation capacity of HO• or SO4•‒, various advanced oxidation processes (AOPs) have demonstrated substantial removal efficiency for ICMs. It is evident that ICMs can be decomposed mainly through (1) deiodination, (2) dehydration, (3) decarboxylation, (4) H-abstraction, (5) hydroxyl addition, (6) hydroxyl substitution, (7) oxidation of alcohol groups, (8) cleavage of amide bond, and (9) amino oxidation. However, during the ICMs removal process, the C-I bonds of ICMs molecules are broken, giving rise to the formation of cytotoxic iodination disinfection by-products (I-DBPs) that are potentially more harmful to the ecosystem and human health than their parent compounds. To better understand the technology gaps, this review elaborates the major AOPs which are effective for ICMs removal and emphasizes on the main degradation routes of ICMs in different oxidation system. Some prevailing concerns and challenges are discussed for optimizing the ICMs treatment process.
Recently, the use of microalgae for bioremediation of pharmaceuticals (PhAs) has attracted increasing interest. However, most studies focused more on microalgae removal performance, its defensive response to the PhAs during wastewater treatment remains unexplored. Herein, microalgal three defensive systems have been investigated in synthetic wastewater, with six PhAs as the typical drug. Results show that PhAs could bind to EPS, and this action in turn could help to alleviate the direct toxicity of PhAs to microalgae. Subsequently, the physiological analyses revealed the increase of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities, potentially reducing the oxidative stress induced by PhAs. Furthermore, the enzyme activities of cytochrome P450 (CYP450) and glutathione-S-transferase (GST) were significantly upregulated after exposure to SMX, CIP and BPA, followed by a significant decrease in biodegradation rates after the addition of CYP450 inhibitors, suggesting that the biotransformation and detoxification of PhAs occurred. Meanwhile, molecular docking further revealed that CYP450 could bind with PhAs via hydrogen bond and hydrophobic interaction, which proved their abilities to be metabolized and form transformation products in microalgae. These findings provide an advancing understanding of microalgae technologies to improve the treatment of wastewater contaminated with PhAs.
UBE2C (Ubiquitin conjugating enzyme E2 C), a key regulator of cell cycle progression, is a promising target for discovery of antitumor agents. However, it is challenging to develop inhibitors of UBE2C owing to its lack of “druggable” pockets. BioPROTACs (biological proteolysis targeting chimeras) are a kind of protein-based degraders by fusing an adaptor to a subunit of E3 ligase for ubiquitination and subsequent proteasome-dependent degradation of target protein. We report herein the design and biological evaluation of a UBE2C-targeting bioPROTAC based on the NEL (novel E3 ligase) domain of bacterial E3 ligase IpaH9.8 and the UBE2C-binding WHB (winged-helix B) domain of APC2 (anaphase promoting complex subunit 2). The in vitro ubiquitination test and Mass Spectrometry analysis showed that the bioPROTAC could transfer ubiquitin to surface exposed lysines on UBE2C and catalyzed the formation of polyubiquitin chains. In addition, the transient co-expression experiment showed that the bioPROTAC could promote proteasomal degradation of heterologous UBE2C and rescue its downstream substrates in mammalian cells.
Extensive application of nuclear energy has caused widespread environmental uranium contamination. New detection approaches without complicated sample pretreatment and precision instruments are in demand for on-site and in-time determination of uranyl ions in environmental monitoring, especially in an emergency situation. In this work, a simple and effective fluorescent sensor (Z)-N'-hydroxy-4-(1,2,2-triphenylvinyl)benzimidamide (TPE-A) with aggregation-induced emission (AIE) character was established and studied. It could realize to detect UO22+ via quenching the fluorescence of its aggregation-induced emission, with good selectivity and sensitivity. Such strategy shows a wide linear range from 5.0 × 10−8 mol/L to 4.5 × 10−7 mol/L (R2 = 0.9988) with exceptional sensitivity reaching 4.7 × 10−9 mol/L, which is far below the limit for uranium in drinking water (30 µg/L, ca. 1.1 × 10−7 mol/L) stipulated by the WHO. A response time less than four minutes make it rapid for uranyl ion measurement. It was applied for detection of uranyl ion in spiked river water samples with recoveries in the range of 98.7%-104.0%, comparable to those obtained by ICP-MS. With the advantages of portable apparatus, rapid detection process and high sensitivity, TPE-A can serve as a promising fluorescent sensor for the detection of UO22+ in environmental water samples.
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