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.
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.
Controllable arrangement of different ligands in a single assembly will not only bring increased complexity but also offers a new route to fine‐tune the function of the designed architecture. We ...report here a combinatorial self‐assembly with enPd(NO3)2 and three different ligands (L1–3), which gave rise to a family of six palladium‐organic cages (C1‐6) with systematically varied shapes and cavities, including three new heteroleptic (Pd5L12L2, Pd5L12L3, Pd4L2L3), one new homoleptic (Pd4L32) cages, and two known homoleptic (Pd6L14, Pd4L22) cages. Emergent functions due to the fusion of two half cavities on the heteroleptic cages from their parent homoleptic cages have been observed: the heteroleptic cages can form ternary complexes by co‐encapsulation of both aromatic and aliphatic guests, while their homoleptic counterparts can only form binary complexes. Such a forced co‐encapsulation effect endows the heteroleptic cages with enhanced catalytic power for the Knoevenagel condensation.
A combinatorial self‐assembly approach gives rise to a family of palladium‐organic cages featuring systematically fine‐tuned shapes and cavities. Emergent guest‐binding and catalytic functions were observed that are due to the fusion of two half cavities on the heteroleptic cages from their parent homoleptic cages.
Atmospheric CO 2 is closely related to the greenhouse effect. Therefore, new practical materials and techniques for highly selective CO 2 adsorption and catalytic conversion are imperative. Covalent ...composites of covalent organic frameworks (COFs) with polymers (oligomers) might be a promising approach to meeting the multifaceted requirements of CO 2 treatment. Herein, a novel COF–chitosan composite aerogel ( COF-IL@chitosan ) was designed and fabricated by chemical crosslinking of an allyl-imidazolium ionic liquid-decorated COF ( COF-IL ) with a thiol-attached chitosan (chitosan–SH) binder via a photoinduced thiol–ene reaction. The crystalline structure, highly selective CO 2 adsorption and catalytic conversion features of COF-IL were found to be well maintained in the composite aerogel. The generated covalently coupled COF–chitosan composite material COF-IL@chitosan was found to be robust, uniform and processable even with a remarkably high COF loading (up to 80 wt%). More importantly, the processable COF-IL@chitosan aerogel could be readily shaped into a simplified fixed-bed reactor model via a facile templated freeze-drying procedure, and a scaled-up recyclable CO 2 cycloaddition reaction was realized.
Atmospheric CO2 is closely related to the greenhouse effect. Therefore, new practical materials and techniques for highly selective CO2 adsorption and catalytic conversion are imperative. Covalent ...composites of covalent organic frameworks (COFs) with polymers (oligomers) might be a promising approach to meeting the multifaceted requirements of CO2 treatment. Herein, a novel COF–chitosan composite aerogel (COF-IL@chitosan) was designed and fabricated by chemical crosslinking of an allyl-imidazolium ionic liquid-decorated COF (COF-IL) with a thiol-attached chitosan (chitosan–SH) binder via a photoinduced thiol–ene reaction. The crystalline structure, highly selective CO2 adsorption and catalytic conversion features of COF-IL were found to be well maintained in the composite aerogel. The generated covalently coupled COF–chitosan composite material COF-IL@chitosan was found to be robust, uniform and processable even with a remarkably high COF loading (up to 80 wt%). More importantly, the processable COF-IL@chitosan aerogel could be readily shaped into a simplified fixed-bed reactor model via a facile templated freeze-drying procedure, and a scaled-up recyclable CO2 cycloaddition reaction was realized.
Imbalances in gut microbiota composition are linked to hypertension, host metabolic abnormalities, systemic inflammation, and other conditions. In the present study, we examined the changes of gut ...microbiota in women with early-onset preeclampsia (PE) and in normotensive, uncomplicated pregnant women during late pregnancy and at 1 and 6 weeks postpartum.
Gut microbiota profiles of women with PE and healthy pregnant women in the third trimester and at 1 and 6 weeks postpartum were assessed by 16S rRNA gene amplicon sequencing. Plasma levels of interleukin-6 (IL-6), intestinal fatty acid-binding protein (I-FABP), zonulin, and lipopolysaccharide (LPS) were measured in the third trimesters.
At the genus level, 8 bacterial genera were significantly enriched in the antepartum samples of PE patients compared to healthy controls, of which
, and
represented the major variances in PE microbiomes. Conversely, 5 genera, including
, and
, were significantly depleted in antepartum PE samples. Maternal blood pressure and liver enzyme levels were positively correlated to the PE-enriched genera such as
, and
, while the fetal features (e.g., Apgar score and newborn birth weight) were positively correlated with PE-depleted genera and negatively correlated with PE-enriched genera. Moreover, maternal blood IL-6 level was positively associated with gut
and
, whereas LPS level was negatively associated with
. In terms of postpartum women, both the gut microbial composition and the PE-associated microbial alterations were highly consistent with those of the antepartum women.
PE diagnosed in the third trimester of pregnancy is associated with a disrupted gut microbiota composition compared with uncomplicated pregnant women, which are associated with maternal clinical features (blood pressure level and liver dysfunction) and newborn birth weight. Moreover, these antepartum alterations in gut microbiota persisted 6 weeks postpartum.
An efficient approach was developed for the synthesis of the well-known BlueCage by pre-bridging two 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT) panels with one linker followed by cage formation in a ...much improved yield and shortened reaction time. Such a stepwise methodology was further applied to synthesize three new pyridinium organic cages, C2, C3, and C4, where the low-symmetry cages C3 and C4 with angled panels demonstrated better recognition properties toward 1,1′-bi-2-naphthol (BINOL) than the high-symmetry analogue C2 featuring parallel platforms.
Bone fracture remains a common occurrence, with a population-weighted incidence of approximately 3.21 per 1000. In addition, approximately 2% to 50% of patients with skeletal fractures will develop ...an infection, one of the causes of disordered bone healing. Dysfunction of bone marrow mesenchymal stem cells (BMSCs) plays a key role in disordered bone repair. However, the specific mechanisms underlying BMSC dysfunction caused by bone infection are largely unknown. In this study, we discovered that Fibulin2 expression was upregulated in infected bone tissues and that BMSCs were the source of infection-induced Fibulin2. Importantly, Fibulin2 knockout accelerated mineralized bone formation during skeletal development and inhibited inflammatory bone resorption. We demonstrated that Fibulin2 suppressed BMSC osteogenic differentiation by binding to Notch2 and inactivating the Notch2 signaling pathway. Moreover, Fibulin2 knockdown restored Notch2 pathway activation and promoted BMSC osteogenesis; these outcomes were abolished by DAPT, a Notch inhibitor. Furthermore, transplanted Fibulin2 knockdown BMSCs displayed better bone repair potential in vivo. Altogether, Fibulin2 is a negative regulator of BMSC osteogenic differentiation that inhibits osteogenesis by inactivating the Notch2 signaling pathway in infected bone.
Stereocontrolled self-assembly of a dinuclear triple-stranded europium helicate (Eu2L3) based on DTE-functionalized ligands has been achieved via the chiral-induction strategy. The point-chirality of ...the ligands is transferred to give either Δ or Λ metal-centers and hence leads to the overall P or M helical senses. CD spectroscopy and NMR enantiomeric differentiation experiments have confirmed the formation of enantiomers. Moreover, the helicates in solution feature reversible photocyclization and cycloreversion, offering an opportunity to develop as chiroptical switches.
To develop superior rice varieties with improved yield in most rainfed areas of Asia/Africa, we started an introgression-breeding program for simultaneously improving yield and tolerances of multiple ...abiotic stresses. Using eight BC1 populations derived from a widely adaptable recipient and eight donors plus three rounds of phenotypic selection, we developed 496 introgression lines (ILs) with significantly higher yield under drought, salt and/or non-stress conditions in 5 years. Six new varieties were released in the Philippines and Pakistan and many more are being evaluated in multi-location yield trials for releasing in several countries. Marker-facilitated genetic characterization revealed three interesting aspects of the breeding procedure: (1) the donor introgression pattern in specific BC populations was characteristic; (2) introgression frequency in different genomic regions varied considerably, resulting primarily from strong selection for the target traits; and (3) significantly lower heterozygosity was observed in BC progenies selected for drought and salinity tolerance. Applying strong phenotypic selection under abiotic stresses in early segregating generations has major advantages for not only improving multiple abiotic stress tolerance but also achieving quicker homozygosity in early generations. This breeding procedure can be easily adopted by small breeding programs in developing countries to develop high-yielding varieties tolerant of abiotic stresses. The large set of trait-specific ILs can be used for genetic mapping of genes/QTL that affect target and non-target traits and for efficient varietal development by designed QTL pyramiding and genomics-based recurrent selection in our Green Super Rice breeding technology.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
