Chiral framework materials have been developed for many applications including chiral recognition, chiral separation, asymmetric catalysis, and chiroptical materials. Herein, we report that an ...achiral cucurbit8uril‐based supramolecular organic framework (SOF‐1) with the dynamic rotational conformation of tetraphenylethene units can exhibit adaptive chirality to produce M‐SOF‐1 or P‐SOF‐1 with mirror‐image circular dichroism (CD) with gabs≈±10−4 and circularly polarized luminescence (CPL) with glum≈±10−4 induced by L‐/D‐phenylalanine in water, respectively. The chirality induction in CD (gabs≈−10−4) and CPL (glum≈−10−4) of P‐SOF‐1 from achiral SOF‐1 can be presented by using a small amount of adenosine‐5′‐triphosphate disodium (ATP) or adenosine‐5′‐diphosphate disodium (ADP) (only 0.4 equiv) in water. Furthermore, the adaptive chirality of SOF‐1 can be used to determine dipeptide sequences (e.g., Phe‐Ala and Ala‐Phe) and distinguish polypeptides/proteins (e.g., somatostatin and human insulin) with characteristic CD spectra. Therefore, achiral SOF‐1 as an ideal chiroptical platform with adaptive chirality may be applied to determine the enantiopurity of amino acids (e.g., L‐/D‐phenylalanine), develop aqueous CPL materials, and distinguish biological chiral macromolecules (e.g., peptides/proteins) via chirality induction in water.
An achiral supramolecular organic framework (SOF) exhibits adaptive chirality with dual circular dichroism and circularly polarized luminescence responses when meeting various chiral guests, including L‐/D‐Phe, adenosine derivatives, and peptides/proteins via chirality induction in water. The adaptive chirality of the SOF can be used as a chiroptical platform to determine the enantiopurity, develop aqueous CPL materials, and distinguish peptides/proteins.
White light‐emitting diodes (WLEDs) are promising next‐generation solid‐state light sources. However, the commercialization route for WLED production suffers from challenges in terms of insufficient ...color‐rendering index (CRI), color instability, and incorporation of rare‐earth elements. Herein, a new two‐component strategy is developed by assembling two broadband emissive materials with self‐trapped excitons (STEs) for high CRI and stable WLEDs. The strategy addresses effectively the challenging issues facing current WLEDs. Based on first‐principles thermodynamic calculations, copper‐based ternary halides composites, CsCu2I3@Cs3Cu2I5, are synthesized by a facile one‐step solution approach. The composites exhibit an ideal white‐light emission with a cold/warm white‐light tuning and a robust stability against heat, ultraviolet light, and environmental oxygen/moisture. A series of cold/warm tunable WLEDs is demonstrated with a maximum luminance of 145 cd m−2 and an external quantum efficiency of 0.15%, and a record high CRI of 91.6 is achieved, which is the highest value for lead‐free WLEDs. Importantly, the fabricated device demonstrates an excellent operation stability in a continuous current mode, exhibiting a long half‐lifetime of 238.5 min. The results promise the use of the hybrids of STEs‐derived broadband emissive materials for high‐performance WLEDs.
Stable and highly luminescent CsCu2I3@Cs3Cu2I5 composites are synthesized through a one‐step spin‐coating method. They exhibit white‐light emission through self‐trapped excitons, as well as cold/warm white‐light tuning. By using the composites as a white‐light emitter, electrically driven cold/warm tunable WLEDs with a record color‐rendering index of 91.6 are successfully demonstrated, and a long half‐lifetime of 238.5 min is achieved.
MicroRNA exhibits differential expression levels in cancer and can affect cellular transformation, carcinogenesis and metastasis. Although fluorescence techniques using dye molecule labels have been ...studied, label-free molecular-level quantification of miRNA is extremely challenging. We developed a surface plasmon resonance sensor based on two-dimensional nanomaterial of antimonene for the specific label-free detection of clinically relevant biomarkers such as miRNA-21 and miRNA-155. First-principles energetic calculations reveal that antimonene has substantially stronger interaction with ssDNA than the graphene that has been previously used in DNA molecule sensing, due to thanking for more delocalized 5s/5p orbitals in antimonene. The detection limit can reach 10 aM, which is 2.3-10,000 times higher than those of existing miRNA sensors. The combination of not-attempted-before exotic sensing material and SPR architecture represents an approach to unlocking the ultrasensitive detection of miRNA and DNA and provides a promising avenue for the early diagnosis, staging, and monitoring of cancer.
Orthorhombic phases for perovskite solar cellsThe power conversion efficiencies (PCEs) of all-inorganic perovskites are lower than those of materials with organic cations. This is in part because ...these materials have larger bandgaps. The cubic crystal phases of these materials also exhibit poor stability. Wang et al. synthesized the orthorhombic β-phase of CsPbI3 from HPbI3 and CsI. The material exhibited higher stability and a more favorable bandgap, which allowed for PCEs of 15%. Passivation of the surface trap state with choline iodide boosted PCEs to 18%.Science, this issue p. 591Although β-CsPbI3 has a bandgap favorable for application in tandem solar cells, depositing and stabilizing β-CsPbI3 experimentally has remained a challenge. We obtained highly crystalline β-CsPbI3 films with an extended spectral response and enhanced phase stability. Synchrotron-based x-ray scattering revealed the presence of highly oriented β-CsPbI3 grains, and sensitive elemental analyses—including inductively coupled plasma mass spectrometry and time-of-flight secondary ion mass spectrometry—confirmed their all-inorganic composition. We further mitigated the effects of cracks and pinholes in the perovskite layer by surface treating with choline iodide, which increased the charge-carrier lifetime and improved the energy-level alignment between the β-CsPbI3 absorber layer and carrier-selective contacts. The perovskite solar cells made from the treated material have highly reproducible and stable efficiencies reaching 18.4% under 45 ± 5°C ambient conditions.
We report the synthesis and characterization of a three‐dimensional tetraphenylethene‐based octacationic cage that shows host–guest recognition of polycyclic aromatic hydrocarbons (e.g. coronene) in ...organic media and water‐soluble dyes (e.g. sulforhodamine 101) in aqueous media through CH⋅⋅⋅π, π–π, and/or electrostatic interactions. The cage⊃coronene exhibits a cuboid internal cavity with a size of approximately 17.2×11.0×6.96 Å3 and a “hamburger”‐type host–guest complex, which is hierarchically stacked into 1D nanotubes and a 3D supramolecular framework. The free cage possesses a similar cavity in the crystalline state. Furthermore, a host–guest complex formed between the octacationic cage and sulforhodamine 101 had a higher absolute quantum yield (ΦF=28.5 %), larger excitation–emission gap (Δλex‐em=211 nm), and longer emission lifetime (τ=7.0 ns) as compared to the guest (ΦF=10.5 %; Δλex‐em=11 nm; τ=4.9 ns), and purer emission (ΔλFWHM=38 nm) as compared to the host (ΔλFWHM=111 nm).
Two‐in‐one: A three‐dimensional tetraphenylethene‐based octacationic cage (see structure), which successfully integrates the properties of fluorescence and host–guest recognition in one molecule, was synthesized in a straightforward manner. The cage was shown to bind polycyclic aromatic hydrocarbons, such as coronene, in organic media and the water‐soluble dye sulforhodamine 101 in aqueous media.
Here we report one-pot synthesis of tetraphenylethene-based tetracationic dicyclophane (1) and its self-assembly behaviors with aggregation-induced emission (AIE) and light-harvesting function. ...Confirmed by X-ray crystal structure and high resolution transmission electron microscopy, this tetracationic dicyclophane can self-assemble into a 3D supramolecular framework to form crystalline nanospheres (2) finally, which exhibits a strong emission (ΦF = 97.7%) via AIE effect in aqueous solution. Interestingly, AIE-active 2 as a single-molecule-based fluorescent supramolecular platform can encapsulate an organic dye (e.g., Nile red) to form light-harvesting nanospheres (3) further with a large red-shift (Δλ = ∼70 nm), highly efficient energy-transfer ability (ΦET = 77.5%), and high antenna effect (14.3).
A Linear Spectral Unmixing method based on Multi-Constraint Endmembers (LSU-MCE) is proposed to extract the sea ice in the Bohai Sea using the Moderate Resolution Imaging Spectroradiometer (MODIS) ...images. The method first extracts the spectral features, texture features, shape features, and temperature features of the sea ice and sea water, and then constructs the rules using the features to purify the endmembers, and finally decomposes the pixels using the linear spectral unmixing method. The method can properly detect sea ice including thin ice, drift ice, and melt ponds. Besides, the turbid sea water is separated from sea water as a separate endmember. So the proposed method can eliminate the disturbance caused by suspended sediment and successfully detect sea ice in high sediment waters. The method has good robustness to MODIS images of different satellites (Terra and Aqua) and the stripe noise. The method has been successfully applied to time series data of MODIS and the results show that it has high accuracy for sea ice detection in the Bohai Sea, with better visual results, and higher overall accuracy and kappa coefficient (
).
The present work highlights recent achievements in development of nanostructured dispersions and biocolloids for drug delivery applications. We emphasize the key role of biological small-angle X-ray ...scattering (BioSAXS) investigations for the nanomedicine design. A focus is given on controlled encapsulation of small molecular weight phytochemical drugs in lipid-based nanocarriers as well as on encapsulation of macromolecular siRNA, plasmid DNA, peptide and protein pharmaceuticals in nanostructured nanoparticles that may provide efficient intracellular delivery and triggered drug release. Selected examples of utilisation of the BioSAXS method for characterization of various types of liquid crystalline nanoorganizations (liposome, spongosome, cubosome, hexosome, and nanostructured lipid carriers) are discussed in view of the successful encapsulation and protection of phytochemicals and therapeutic biomolecules in the hydrophobic or the hydrophilic compartments of the nanocarriers. We conclude that the structural design of the nanoparticulate carriers is of crucial importance for the therapeutic outcome and the triggered drug release from biocolloids.
Protein-loaded liquid crystalline lipid nanoparticle (left) and calculated small-angle X-ray scattering (SAXS) curves of biocolloidal dispersions (right). Display omitted
•Progress in lipid-based nanostructured dispersions for drug delivery applications highlighted•Key role of the structure determinations via the SAXS method for the nanomedicine design emphasized•Features of nanocarrier structural design for delivery of macromolecular drugs and anticancer phytochemicals outlined
Herein, we report an achiral anthracene‐based tetracationic nanotube (1⋅4Cl−) that shows two levels of supramolecular chirality: namely, conformationally adaptive host–guest complexation with ...nucleoside triphosphates (e.g. ATP, GTP, CTP, and UTP) and twisted packing of the chiral host–guest complexes in water. Interestingly, achiral 1⋅4Cl− exhibits chiral recognition for ATP/GTP and CTP/UTP through structural transformation of its intramolecular M‐ and P‐twisted conformation as the first level of supramolecular chirality, which leads to adaptive chirality with opposite CD responses. Furthermore, the formation of chiral M‐1⋅4Cl−⊃ATP can promote an intermolecular P‐twisted dimeric packing of anthracene rings as the second level of supramolecular chirality to achieve assembled chirality with strong circularly polarized luminescence arising from the excimer ((+)‐CPL, glum≈10−2) in water.
Host–guest complexation with nucleoside triphosphates in water has led to an achiral anthracene‐based tetracationic nanotube showing two levels of supramolecular chirality. This nanotube, which can adopt M‐ and P‐twisted conformations, exhibits adaptive chiral recognition with opposite CD spectra for ATP/GTP and CTP/UTP, and a strong excimer showing strong circularly polarized luminescence ((+)‐CPL; glum≈10−2) with ATP in water.
Abstract
Background
Cross-sectional and longitudinal studies have found that problematic mobile phone use, bedtime procrastination, sleep quality, and depressive symptoms are strongly associated. ...However, studies are inconsistent regarding whether problematic mobile phone use predicts depressive symptoms or vice versa, and sleep factors have been infrequently focused on in this regard. In addition, few studies have examined the longitudinal associations and directions of effects between these factors. Therefore, this study aims to explore the longitudinal relationship among problematic mobile phone use, bedtime procrastination, sleep quality, and depressive symptoms in college students.
Methods
Overall, 1181 college students completed questionnaires on problematic mobile phone use, bedtime procrastination, sleep quality, and depressive symptoms at two time points 12 months apart. A cross-lagged model was used to examine the longitudinal relationship between these factors.
Results
Cross-lagged analyses showed significant bidirectional relationships of problematic mobile phone use with bedtime procrastination and depressive symptoms. Additionally, there were also significant bidirectional relationships of sleep quality with bedtime procrastination and depressive symptoms. Problematic mobile phone use predicted subsequent sleep quality one-way, and bedtime procrastination predicted subsequent depressive symptoms one-way.
Conclusions
This study further expands our understanding of the longitudinal and bidirectional relationships among problematic mobile phone use, bedtime procrastination, sleep quality and depressive symptoms and helps school mental health educators design targeted interventions to reduce problematic mobile phone use, sleep problems, and depressive symptoms among college students.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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