Transformations within container-molecules provide a good alternative between traditional homogeneous and heterogeneous catalysis, as the containers themselves can be regarded as single molecular ...nanomicelles. We report here the designed-synthesis of a water-soluble redox-active supramolecular Pd4L2 cage and its application in the encapsulation of aromatic molecules and polyoxometalates (POMs) catalysts. Compared to the previous known Pd6L4 cage, our results show that replacement of two cis-blocked palladium corners with p-xylene bridges through pyridinium bonds formation between the 2,4,6-tri-4-pyridyl-1,3,5-triazine (TPT) ligands not only provides reversible redox-activities for the new Pd4L2 cage, but also realizes the expansion and subdivision of its internal cavity. An increased number of guests, including polyaromatics and POMs, can be accommodated inside the Pd4L2 cage. Moreover, both conversion and product selectivity (sulfoxide over sulfone) have also been much enhanced in the desulfurization reactions catalyzed by the POMs@Pd4L2 host–guest complexes. We expect that further photochromic or photoredox functions are possible taking advantage of this new generation of organo-palladium cage.
Sodium‐ion batteries (SIBs) are considered as a low‐cost complementary or alternative system to prestigious lithium‐ion batteries (LIBs) because of their similar working principle to LIBs, ...cost‐effectiveness, and sustainable availability of sodium resources, especially in large‐scale energy storage systems (EESs). Among various cathode candidates for SIBs, Na‐based layered transition metal oxides have received extensive attention for their relatively large specific capacity, high operating potential, facile synthesis, and environmental benignity. However, there are a series of fatal issues in terms of poor air stability, unstable cathode/electrolyte interphase, and irreversible phase transition that lead to unsatisfactory battery performance from the perspective of preparation to application, outside to inside of layered oxide cathodes, which severely limit their practical application. This work is meant to review these critical problems associated with layered oxide cathodes to understand their fundamental roots and degradation mechanisms, and to provide a comprehensive summary of mainstream modification strategies including chemical substitution, surface modification, structure modulation, and so forth, concentrating on how to improve air stability, reduce interfacial side reaction, and suppress phase transition for realizing high structural reversibility, fast Na+ kinetics, and superior comprehensive electrochemical performance. The advantages and disadvantages of different strategies are discussed, and insights into future challenges and opportunities for layered oxide cathodes are also presented.
Recent progress in layered oxide cathodes for sodium‐ion batteries (SIBs) from air stability, interface chemistry, and phase transition are comprehensively summarized. The intrinsic degradation mechanisms behind electrochemical performance and mainstream modification strategies are systematically sorted out and analyzed. The remaining challenges, promising optimization strategies as well as endeavor directions to break current limitations are also presented for the future design of high‐performance layered oxide cathodes for SIBs.
Artificial hosts with rich conformational dynamics are attractive to supramolecular chemists due to their adaptive guest‐binding properties and enzyme‐like catalytic functions. We report here the ...adaptive self‐assembly and host‐guest catalysis of a new water‐soluble organo‐palladium host (Pd2L2) built from a pyridinium‐bonded macrocyclic ligand (L) and cis‐blocked palladium corners (Pd). While the direct self‐assembly of L with Pd gives rise to a dynamic mixture of products, both neutral polyaromatic hydrocarbons and an anionic polyoxometalate cluster (W10O324−) can template the dominant formation of the Pd2L2 host. Guest‐adaptive conformational changes and induced‐fit cavity deformation of the Pd2L2 host have been clearly observed in the crystal structures. Moreover, the installation of the electron‐rich W10O324− cluster within the cationic redox‐active host (W10O32⊂Pd2L2) facilitates the efficient and selective C−H photooxidation of toluene derivatives to aldehyde products under mild conditions, thus representing an ideal platform for green supramolecular catalysis.
Induced‐fit self‐assembly using a pyridinium‐based dynamic macrocyclic ligand gives rise to a new water‐soluble adaptive organo‐palladium host. Co‐encapsulation of both an electron‐rich W10O324− cluster and toluene derivatives within the redox‐active host facilitates efficient and selective C−H photooxidation under mild conditions.
Chiral luminescent lanthanide–organic cages have many potential applications in enantioselective recognition, sensing, and asymmetric catalysis. However, due to the paucity of structures and their ...limited cavities, host–guest chemistry with lanthanide–organic cages has remained elusive so far. Herein, we report a guest-driven self-assembly and chiral induction approach for the construction of otherwise inaccessible Ln4L4-type (Ln = lanthanide ions, i.e., EuIII, TbIII; L = ligand) tetrahedral hosts. Single crystal analyses on a series of host–guest complexes reveal remarkable guest-adaptive cavity breathing on the tetrahedral cages, reflecting the advantage of the variation tolerance on coordination geometry of the f-elements. Meanwhile, noncovalent confinement of pyrene within the lanthanide cage not only leads to diminishment of its excimer emission but also facilitates guest to host energy transfer, opening up a new sensitization window for the lanthanide luminescence on the cage. Moreover, stereoselective self-assembly of either Λ4- or Δ4- type Eu4L4 cages has been realized via chiral induction with R/S-BINOL or R/S-SPOL templates, as confirmed by NMR, circular dichroism (CD), and circularly polarized luminescence (CPL) with high dissymmetry factors (g lum) up to ±0.125.
Previous phylogenetic analyses of species within the genus Golovinomyces (Ascomycota, Erysiphales), based on ITS and 28S rDNA sequence data, revealed a co-evolutionary relationship between powdery ...mildew species and hosts of certain tribes of the plant family Asteraceae. Golovinomyces growing on host plants belonging to the Heliantheae formed a single lineage, comprised of a morphologically differentiated complex of species, which included G. ambrosiae, G. circumfusus, and G. spadiceus. However, the lineage also encompassed sequences retrieved from Golovinomyces specimens on other Asteraceae tribes as well as other plant families, suggesting the involvement of a plurivorous species. A multilocus phylogenetic examination of this complex, using ITS, 28S, IGS (intergenic spacer), TUB2 (beta-tubulin), and CHS1 (chitin synthase I) sequence data was carried out to clarify the discrepancies between ITS and 28S rDNA sequence data and morphological differences. Furthermore, the circumscription of species and their host ranges were emended.
The phylogenetic and morphological analyses conducted in this study revealed three distinct species named, viz., (1) G. ambrosiae emend. (including G. spadiceus), a plurivorous species that occurs on a multitude of hosts including, Ambrosia spp., multiple species of the Heliantheae and plant species of other tribes of Asteraceae including the Asian species of Eupatorium; (2) G. latisporus comb. nov. (≡ Oidium latisporum), the closely related, but morphologically distinct species confined to hosts of the Heliantheae genera Helianthus, Zinnia, and most likely Rudbeckia; and (3) G. circumfusus confined to Eupatorium cannabinum in Europe.
The present results provide strong evidence that the combination of multi-locus phylogeny and morphological analysis is an effective way to identify species in the genus Golovinomyces.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We report here a guest‐reaction‐induced mitosis‐like host transformation from a known Pd4L2 cage 1 to a conjoined Pd6L3 twin‐cage 2 featuring two separate cavities. The encapsulation of ...1‐hydroxymethyl‐2‐naphthol (G1), a known ortho‐quinone methide (o‐QMs) precursor, within the hydrophobic cavity of cage 1 is found crucial to realize the cage to twin‐cage conversion. Confined G1 molecules within the nanocavity undergo self‐coupling dimerization reaction to form 2,2′‐dihydroxy‐1,1′‐dinaphthylmethane (G2) which then triggers the cage to twin‐cage mitosis. The same conversion also proceeds, in a much faster rate, via the direct templation of G2, confirming the induced‐fit transformation mechanism. The structure of the (G2)2⊂2 host–guest complex has been established by X‐ray crystallographic study, where cis‐ to trans‐ conformational switch on one bridging ligand is revealed.
A host was transformed from Pd4L2 cage 1 to an unprecedented conjoined Pd6L3 twin‐cage 2. This mitosis‐like transformation was induced by a guest reaction.
Objective
To analyse the histopathological features of eosinophilic sialodochitis by using terminal duct biopsy.
Methods
Sixty‐five patients with suspected eosinophilic sialodochitis and four with ...chronic obstructive sialadenitis were prospectively enrolled. Clinical features, laboratory tests and sialograms were comparatively analysed. Terminal duct biopsy of the parotid or submandibular glands was performed concomitantly with endoscopy‐assisted duct dilatation to determine the histopathological features of eosinophilic sialodochitis.
Results
Based on eosinophil quantification, the samples of suspected patients were scored as ‘definite’, ‘highly suspected’ and ‘negative’ in 26 (40%), 15 (23.1%) and 24 (36.9%) cases, respectively. Gland types and peripheral blood eosinophil counts were significantly different among these three groups. The proportions of itching glands, mucus plug exudations and elevated immunoglobulin E levels were higher in the ‘definite’ group than in the other two groups; however, the intergroup differences were insignificant. The primary pathological features of eosinophilic sialodochitis were abundant eosinophils and lymphocytes infiltrated around the duct, degranulation of eosinophils, extensive fibrosis and scattered mastocytes. Periductal eosinophils were not found in cases of chronic obstructive sialadenitis.
Conclusion
Our findings suggest that terminal duct biopsy is safe and valuable for the pathological confirmation of eosinophilic sialodochitis, and can be used simultaneously with endoscopy‐assisted duct dilatation.
The aim of this study was to explore the endoscopic characteristics of radioactive iodine-induced sialadenitis (RAIS), and to evaluate the treatment outcomes of endoscopic intervention for RAIS.
...Retrospective case series.
Eighty-two consecutive patients (11 males and 71 females) diagnosed as RAIS from Nov. 2012 to Sep. 2023 were retrospectively included. All patients underwent endoscopic exploration and intervention of the affected glands. The endoscopic features were collected, and treatment outcomes were followed-up and evaluated through post to pre-operative comparisons of gland status.
Overall, endoscopic procedures were undertaken for 162 parotid glands (PGs) and 62 submandibular glands (SMGs). Endoscopy showed severe lumen stricture (49.3%) and ductal atresia (23.5%) in PGs, as well as severe stenosis of the anterior duct and ectasia of the proximal duct (59.7%) in SMGs. During a median six months' follow-up, the treatment outcomes of PGs were evaluated as "improvement" in 23.4%，"lesion maintenance" in 45.1% and "lesion aggravation" in 31.5% of the glands. As for SMGs, the treatment outcomes were scored as "improvement"in 29.0%，"lesion maintenance"in 54.8%, and"lesion aggravation"in 16.1% of the glands. No significant differences of treatment outcomes were found relative to RAI treatment sessions and cumulative dosage.
RAIS is characteristic of severe lumen stricture and ductal atresia in PGs, and stenosis of the distal duct and ectasia of the proximal duct in SMGs. Endoscopy can alleviate clinical symptoms of RAIS and help to preserve the gland function.
4 Laryngoscope, 2024.
Brønsted-base active sites on a Pd4L2 cage facilitates enhanced catalytic efficiency, wide substrate scope and high turnover number (TON) for the one-pot photooxidation/Knoevenagel condensation ...reaction under mild conditions.
One important feature of enzyme catalysis is the induced-fit conformational change after binding substrates. Herein, we report a biomimetic water-soluble molecular capsule featuring adaptive ...structural change toward substrate binding, which offers an ideal platform for efficient photocatalysis. The molecular capsule was coordination-assembled from three anthracene-bridged bis-TPT TPT = 2,4,6-tris(4-pyridyl)-1,3,5-triazine ligands and six (bpy)Pd(NO3)2 (bpy = 2,2′-bipyridine). Once substrates bind to its hydrophobic cavity, this capsule would undergo quantitative capsule-to-bowl transformation. Visible-light absorption brought about by both the anthracene units and the charge-transfer absorption on the late-formed quintuple π–π stacked host–guest complex efficiently facilitates aerobic photooxidation for the sulfide guests by visible-light irradiation under mild conditions. Desired turnover numbers and product selectivity (sulfoxide over sulfone) have been achieved by the transformable nature of the catalyst and the hydrophilicity of the sulfoxide product. Such a photocatalytic process enabled by an adaptive coordination capsule and substrates as the allosteric effector paves the way for constructing artificial systems to mimic enzyme catalysis.
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