Macrocyclic hosts with a well‐defined cavity are particularly appealing for supramolecular chemistry, but they are still rare. In this research, we reported a new class of macrocyclic hosts, namely ...methylene‐bridged naphthotubes, with well‐defined cavities. They were synthesized through TFA‐catalyzed Friedel–Crafts reactions between alkoxy‐substituted bisnaphthalenes and paraformaldehyde. A configurational selection was observed. Three‐membered macrocycles possess a single cavity, while four‐membered macrocycles adopt a double‐cavity conformation or a self‐filling conformation depending on the alkoxy length. The small homologue shows quite strong binding affinities (up to 108 M−1) to organic cations, which is better than structurally similar but flexible macrocycles. This demonstrates the advantage of a well‐defined cavity in molecular recognition. Moreover, these naphthotubes can be used as chirality sensors for chiral organic cations through different chirality transfer mechanisms.
Methylene‐bridged naphthotubes have been successfully developed. The three‐membered naphthotubes possess a rigid and well‐defined cavity, while four‐membered naphthotubes possess a double‐cavity conformation or a self‐filling conformation depending on the alkoxy length. They show quite strong binding affinities (up to 108 M−1) to organic cations and can be used as chirality sensors for chiral organic cations.
Many strategies have been developed for constructing anisotropic hydrogels, however, it remains a challenge to fabricate hydrogels with anisotropic nanocrystalline domains from intrinsically soft ...networks. Here, we report a naphthotube‐based polyrotaxane‐containing hydrogel that can be reinforced via mechanical training. During the training process, the hydrogel can adopt reorientation of polymer chains to form anisotropic structures driven by external uniaxial force. Due to the multiple hydrogen bonding sites and movable feature of naphthotube, the sliding of naphthotube on PEG chains simultaneously inducing the zipping of adjacent polymer chains to form densely anisotropic nanocrystalline domains through hydrogen bonded networks. Thus, the trained hydrogel exhibits an enhanced tension stress of ≈110 kPa, which realize a remarkable enhancement of ≈10 times compare to initial state. This study provides a new tactic for improving the mechanical performance of soft materials.
A naphthotube‐based polyrotaxane‐containing hydrogel was constructed through one‐pot photo‐initiated copolymerization. Naphthotube can slide along the PEG chain upon repeated stretching. The slide motion further induces the zipping of adjacent polymer chains to form compact hydrogen bonded nanocrystalline domains through integrated hydrogen bonds, which enabled the hydrogel to achieve reinforcement.
Precise binding towards structurally similar substrates is a common feature of biomolecular recognition. However, achieving such selectivity—especially in distinguishing subtle differences in ...substrates—with synthetic hosts can be quite challenging. Herein, we report a novel design strategy involving the combination of different rigid skeletons to adjust the distance between recognition sites within the cavity, which allows for the highly selective recognition of hydrogen‐bonding complementary substrates, such as 4‐chromanone. X‐ray single‐crystal structures and density functional theory calculations confirmed that the distance of endo‐functionalized groups within the rigid cavity is crucial for achieving high binding selectivity through hydrogen bonding. The thermodynamic data and molecular dynamics simulations revealed a significant influence of the hydrophobic cavity on the binding affinity. The new receptor possesses both high selectivity and high affinity, which provide valuable insights for the design of customized receptors.
Endo‐functionalized hosts with different rigid skeletons were successfully synthesized. The well‐controlled distances of the recognition sites within the hydrophobic cavities enable the highly selective recognition of structurally similar guests. This approach presents a viable solution for achieving the precise recognition of specific guests in aqueous environments through adjustments in the distance of recognition sites.
Abstract
Developing chiral receptors with an endo-functionalized cavity for chiral recognition is of great significance in the field of molecular recognition. This study presents two pairs of chiral ...naphthotubes containing a bis-thiourea endo-functionalized cavity. Each chiral naphthotube has two homochiral centers which were fixed adjacent to the thiourea groups, causing the skeleton and thiourea groups to twist enantiomerically through chiral transfer. These chiral naphthotubes are highly effective at enantiomerically recognizing various neutral chiral molecules with an enantioselectivity up to 17.0. Furthermore, the mechanism of the chiral recognition has been revealed to be originated from differences in multiple non-covalent interactions. Various factors, such as the shape of cavities, substituents of guests, flexibility of host and binding modes are demonstrated to contribute to creating differences in the non-covalent interactions. Additionally, the driving force behind enantioselectivity is mainly attributed to enthalpic differences, and enthalpy -entropy compensation has also been observed to influence enantioselectivity.
High thermal conductivity seriously hinders the application and development of eco-friendly SnTe thermoelectric material. Here, entropy and heterogeneous interface were designed to reduce the thermal ...conductivity of SnTe thermoelectric material. SnTe and Sn
0.7-
x
Mn
x
Pb
0.3
Te
0.7
Se
0.3
(
x
= 0, 0.06, 0.09) samples were synthesized via vacuum melting reaction and spark plasma sintering. Pb and Se were introduced into the SnTe, which results in valence band convergence according to density functional theory calculations. To further improve the thermoelectric performance, the Mn elements were also introduced into above system, and the lowest lattice thermal conductivity achieved 0.48 W m
−1
K
−1
at 773 K via the phonon scattering of the configurational entropy and the heterogeneous interface of MnSe precipitates for Sn
0.61
Mn
0.09
Pb
0.3
Te
0.7
Se
0.3
sample. The maximum
ZT
value of 0.85 at 773 K accompanied by the ultralow lattice thermal conductivity in Sn
0.61
Mn
0.09
Pb
0.3
Te
0.7
Se
0.3
sample, which increased by ~ 113% than SnTe. The chaotic entropy engineering could be an efficient way to decrease the lattice thermal conductivity, and the strategy can be extended to thermoelectric materials, thermal barrier materials, thermal insulation materials fields, etc.
Obesity and insulin resistance (IR) are common features of polycystic ovary syndrome (PCOS). Metformin (MET) increases insulin sensitivity, but it is associated with unsatisfactory weight loss. The ...glucagon-like peptide-1 receptor agonist exenatide has been shown to reduce weight and IR in patients with diabetes. This study aimed to explore the therapeutic effects of exenatide once-weekly (QW) combined with MET on body weight, as well as metabolic and endocrinological parameters in overweight/obese women with PCOS.
Fifty overweight/obese women with PCOS diagnosed via the Rotterdam criteria were randomized to one of two treatment groups: MET (500 mg three times a day TID) or combination treatment (COM) (MET 500 mg TID, exenatide 2 mg QW) for 12 weeks. The primary outcomes were anthropometric changes associated with obesity, and the secondary outcomes included changes in reproductive hormone levels, glucose and lipid metabolism, and C-reactive protein.
Forty (80%) patients completed the study. COM therapy was superior to MET monotherapy in reducing weight (P = 0.045), body mass index (BMI) (P = 0.041), and waist circumference (P = 0.023). Patients in the COM group on an average lost 3.8 ± 2.4 kg compared with 2.1 ± 3.0 kg in the MET group. In the COM group, BMI and waist circumference decreased by 1.4 ± 0.87 kg/m2 and 4.63 ± 4.42 cm compared with 0.77 ± 1.17 kg/m2 and 1.72 ± 3.07 cm in the MET group, respectively. Moreover, levels of fasting glucose, oral glucose tolerance test (OGTT) 2-h glucose, and OGTT 2-h insulin were significantly lower with COM therapy than with MET (P < 0.050). Mild and moderate gastrointestinal reactions were the most common adverse events in both groups.
COM therapy was more effective than MET alone in reducing body weight, BMI, and waist circumference, and improving insulin sensitivity in overweight/obese women with PCOS, with acceptable short-term side effects.
ClinicalTrials.gov, NCT04029272. https://clinicaltrials.gov/ct2/show/NCT04029272.
In higher plants, DREB1/CBF-type transcription factors play an important role in tolerance to low temperatures, drought, and high-salt stress. These transcription factors bind to CRT/DRE elements in ...promoter regions of target genes, regulating their expression. In this study, we cloned and characterized a novel gene encoding a DREB1 transcription factor from dwarf apple, Malus baccata (GenBank accession number: EF582842). Expression of MbDREB1 was induced by cold, drought, and salt stress, and also in response to exogenous ABA. Subcellular localization analyses revealed that MbDREB1 localizes in the nucleus. A yeast activity assay demonstrated that the MbDREB1 gene encodes a transcription activator, which specifically binds to DRE/CRT elements. Compared with wild-type plants, transgenic Arabidopsis overexpressing MbDREB1 showed increased tolerance to low temperature, drought, and salt stresses. Analysis of the MbDREB1 promoter revealed an ABA-responsive element (ABRE), an inducer of CBF expression 1 (ICE1)-like binding site, two MYB recognition sites, and three stress-inducible GT-1 boxes. GUS activities driven by the MbDREB1 promoter in transgenic Arabidopsis increased in response to ABA, cold temperature, drought, and salt treatments. Interestingly, the expression of both ABA-independent and ABA-dependent stress-induced genes (COR15a and rd29B, respectively) was activated under normal growth conditions in Arabidopsis overexpressing MbDREB1. These results suggest that MbDREB1 functions as a transcription factor and increases plant tolerance to low temperature, drought, and salt stress via both ABA-dependent and ABA-independent pathways.
Oxidative dissolution of Fe sulfides is an important geochemical process mediating As mobility in aqueous environments. However, little is known regarding the presence of As(III) on the oxidative ...dissolution rate of FeS and on speciation of secondary Fe minerals under pH-neutral and alkaline conditions. In this study, oxidative dissolution of FeS under different concentrations of As(III) and pHs were carried out. The enhanced dissolution rates of Fe(II) from FeS with increasing As(III) concentrations (≤4.7mM) indicate that strong interactions between As(III) and S(−II) in FeS enhance the dissolution rates of structural Fe(II), whereas such an enhancement cannot be observed in the As(III)-FeS system under anoxic conditions at pHs7.0 and 9.0, suggesting the importance of dissolved oxygen in the enhanced dissolution of FeS by As(III). On the other hand, >98.5% of 6.7 and 4.7mM As(III) can be immobilized by 2gL−1 FeS within 1.5h at pHs7.0 and 9.0, respectively, demonstrating the high efficiency of amorphous FeS in the immobilization of concentrated As(III) under oxic conditions. XPS analysis further reveals that, irrespective of pH and initial As(III) concentrations, >60% As(III) was oxidized to As(V) before it was immobilization in secondary Fe minerals, and no As-S compound could be observed after 48h of oxidation. As(III) also influences speciation of secondary Fe minerals during oxidative dissolution of FeS. Analyses of XRD, FTIR, Raman, SEM and TEM demonstrate that the plate lepidocrocite is the primary oxidation product in the absence of As(III), but shows degenerations with increasing As(III) concentrations, and completely changes to ferric arsenate in the presence of 6.7mM As(III), revealing the inhibition of As(III) and/or As(V) on the development of lepidocrocite at pHs7.0 and 9.0. This also suggests that, apart from adsorption, coprecipitation of ferric arsenate is another important pathway to immobilize concentrated As(III) during oxidative dissolution of FeS.
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Polyaniline (PANI) was synthesized by adsorption double oxidizer method, and then reduced with N
2
H
4
·H
2
O (r-PANI), doped with HClO
4
(d-PANI). PANI with different states was combined with ...lithium iron phosphate (LiFePO
4
) in water-based slurry to form PANI/LFP composites. Some physical characterization methods (Fourier transform infrared spectroscopy analysis, scanning electron microscope) were used to analyze the morphology and structure of the composites. The electrochemical properties were characterized by cyclic voltammetry, impedance spectroscopy, galvanostatic charge/discharge, and rate capability. The specific capacity of the r-PANI/LFP composite reached 154 mAh/g, which was 4.1% higher than that of pure LFP, and the coulombic efficiency of the battery was close to 100%. Under the higher discharge rate conditions, the r-PANI/LFP composite still released a good reversible capacity. Moreover, the cyclability and rate capability of the r-PANI/LFP composites are better than that of pure LFP.
MiRNAs have been recognized for their potential in cancer therapeutics, and multiple miRNAs were suggested to affect target genes expression. To overcome limitations of free synthetic miRNAs, such as ...easily degraded in biofluids and limited in cellular uptake, novel miRNAs delivery systems need to be developed.
Using surface-functionalizing technique, poly(D,L-lactide-co-glycolide)/poly(L-lactide)-block-poly(ethylene glycol)-folate polymer nanoparticle (PLGA/PLA-PEG-FA) loaded with miR-204-5p (FA-NPs-miR-204) was developed. The therapeutic efficacy of FA-NPs-miR-204 was evaluated in the Luc-HT-29 xenograft tumor model
.
FA-NPs-miR-204 could be taken up by HT-29 and HCT-116 cells efficiently, resulting in significant inhibitory effect on cell proliferation and promotive effect on cell apoptosis.
study showed that FA-NPs-miR-204 could exert tumor suppressive function in Luc-HT-29 xenograft model.
Our study demonstrates a convenient miRNA delivery system that targets tumor tissue and exerts tumor suppressive function, thus demonstrating a potential new therapeutic option for colon cancer.
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