Interaction between disease-microbiome associations and ageing has not been explored in detail. Here, using age/region-matched sub-sets, we analysed the gut microbiome differences across five major ...diseases in a multi-cohort dataset constituting more than 2500 individuals from 20 to 89 years old. We show that disease-microbiome associations display specific age-centric trends. Ageing-associated microbiome alterations towards a disease-like configuration occur in colorectal cancer patients, thereby masking disease signatures. We identified a microbiome disease response shared across multiple diseases in elderly subjects that is distinct from that in young/middle-aged individuals, but also a novel set of taxa consistently gained in disease across all age groups. A subset of these taxa was associated with increased frailty in subjects from the ELDERMET cohort. The relevant taxa differentially encode specific functions that are known to have disease associations.
Palladium catalyzed cross-coupling reactions represent a significant advancement in contemporary organic synthesis as these reactions are of strategic importance in the area of pharmaceutical drug ...discovery and development. Supported palladium-based catalysts are highly sought-after in carbon-carbon bond forming catalytic processes to ensure catalyst recovery and reuse while preventing product contamination. This paper reports the development of heterogeneous Pd-based bimetallic catalysts supported on fumed silica that have high activity and selectivity matching those of homogeneous catalysts, eliminating the catalyst's leaching and sintering and allowing efficient recycling of the catalysts. Palladium and base metal (Cu, Ni or Co) contents of less than 1.0 wt% loading are deposited on a mesoporous fumed silica support (surface area SA
BET
= 350 m
2
g
−1
) using strong electrostatic adsorption (SEA) yielding homogeneously alloyed nanoparticles with an average size of 1.3 nm. All bimetallic catalysts were found to be highly active toward Suzuki cross-coupling (SCC) reactions with superior activity and stability for the CuPd/SiO
2
catalyst. A low CuPd/SiO
2
loading (Pd: 0.3 mol%) completes the conversion of bromobenzene and phenylboronic acid to biphenyl in 30 minutes under ambient conditions in water/ethanol solvent. In contrast, monometallic Pd/SiO
2
(Pd: 0.3 mol%) completes the same reaction in three hours under the same conditions. The combination of Pd with the base metals helps in retaining the Pd
0
status by charge donation from the base metals to Pd, thus lowering the activation energy of the aryl halide oxidative addition step. Along with its exceptional activity, CuPd/SiO
2
exhibits excellent recycling performance with a turnover frequency (TOF) of 280 000 h
−1
under microwave reaction conditions at 60 °C. Our study demonstrates that SEA is an excellent synthetic strategy for depositing ultra-small Pd-based bimetallic nanoparticles on porous silica for SCC. This avenue not only provides highly active and sintering-resistant catalysts but also significantly lowers Pd contents in the catalysts without compromising catalytic activity, making the catalysts very practical for large-scale applications.
Heterogeneous Pd-based bimetallic catalysts supported on fumed silica with high activity and selectivity matching those of homogeneous catalysts have been developed for carbon-carbon cross-coupling reactions.
This work reports the design and development of a new class of highly active Pd nanocatalysts supported on substoichiometric oxides. These novel catalysts are generated by green laser synthesis ...methods to generate high-surface-area substoichiometric oxide nanoparticles followed by photoreduction in aqueous solutions to deposit highly active Pd nanocatalysts within the surface defects of the oxides. The laser methods eliminate the use of toxic chemicals, including hazardous solvents and chemical reducing agents, and allow efficient reduction of the Pd ions in aqueous solutions aided by the photogenerated electrons from the semiconductor support. The Pd catalysts incorporated within these oxides exhibit high activity for carbon–carbon bond-forming reactions. The Pd/TiO2 catalyst with 0.3 mol % Pd achieves 100% conversion in the reaction between bromobenzene and benzeneboronic acid to the biphenyl product within 240 minutes at room temperature without any external heating. With a catalyst loading of 0.3 mol % Pd in the microwave-assisted reaction between bromobenzene and benzeneboronic acid at 60 °C, 92 and 83% conversions to the biphenyl product are achieved within 5 min of reaction time using the Pd/TiO2 and Pd/ZnO catalysts, respectively. The results demonstrate a remarkable catalytic activity of the substoichiometric oxide-supported Pd catalysts with turnover frequencies (TOF, h–1) of 24 000, 10 000, and 3200 achieved under mirowave-assisted reactions at 60 °C for the 0.03 mol% Pd of the Pd/TiO2, Pd/ZnO, and Pd/ZrO2 catalysts, respectively. The high activity and good reusability of these nanocatalysts are attributed to the optimum catalyst–support interaction between the small Pd nanoparticles and the surface defects of the substoichiometric oxide support prepared by the laser vaporization-controlled condensation method.
Carbyne, an interesting synthetic intermediate, has recently been generated from hypervalent iodine precursors
photoredox catalysis. Given the underexplored chemistry of carbyne, due to the paucity ...of carbyne sources, we are intrigued to discover a new source for this reactive species from classical reagents - phosphonium ylides. Our novel strategy employing phosphonium ylides in an olefin hydrocarbonation reaction features a facile approach for constructing carbon-carbon bonds through metal-free and benign reaction conditions. Moreover, the hydrocarbonation products were delivered in a highly regioselective manner.
Key aspects of microbiome research are the accurate identification of taxa and the profiling of their functionality. Amplicon profiling based on the 16S ribosomal DNA sequence is a ubiquitous ...technique to identify and profile the abundance of the various taxa. However, it does not provide information on their encoded functionality. Predictive tools that can accurately extrapolate the functional information of a microbiome based on taxonomic profile composition are essential. At present, the applicability of these tools is limited due to requirement of reference genomes from known species. We present IPCO (Inference of Pathways from Co-variance analysis), a new method of inferring functionality for 16S-based microbiome profiles independent of reference genomes. IPCO utilises the biological co-variance observed between paired taxonomic and functional profiles and co-varies it with the queried dataset.
IPCO outperforms other established methods both in terms of sample and feature profile prediction. Validation results confirmed that IPCO can replicate observed biological associations between shotgun and metabolite profiles. Comparative analysis of predicted functionality profiles with other popular 16S-based functional prediction tools showed significantly lower performances with predicted functionality showing little to no correlation with paired shotgun features across samples.
IPCO can infer functionality from 16S datasets and significantly outperforms existing tools. IPCO is implemented in R and available from https://github.com/IPCO-Rlibrary/IPCO.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Herein, we report on the synthesis of ultrasmall Pd nanoclusters (∼2 nm) protected by L‐cysteine HOCOCH(NH2)CH2SH ligands (Pdn(L‐Cys)m) and supported on the surfaces of CeO2, TiO2, Fe3O4, and ZnO ...nanoparticles for CO catalytic oxidation. The Pdn(L‐Cys)m nanoclusters supported on the reducible metal oxides CeO2, TiO2 and Fe3O4 exhibit a remarkable catalytic activity towards CO oxidation, significantly higher than the reported Pd nanoparticle catalysts. The high catalytic activity of the ligand‐protected clusters Pdn(L‐Cys)m is observed on the three reducible oxides where 100 % CO conversion occurs at 93–110 °C. The high activity is attributed to the ligand‐protected Pd nanoclusters where the L‐cysteine ligands aid in achieving monodispersity of the Pd clusters by limiting the cluster size to the active sub‐2‐nm region and decreasing the tendency of the clusters for agglomeration. In the case of the ceria support, a complete removal of the L‐cysteine ligands results in connected agglomerated Pd clusters which are less reactive than the ligand‐protected clusters. However, for the TiO2 and Fe3O4 supports, complete removal of the ligands from the Pdn(L‐Cys)m clusters leads to a slight decrease in activity where the T100% CO conversion occurs at 99 °C and 107 °C, respectively. The high porosity of the TiO2 and Fe3O4 supports appears to aid in efficient encapsulation of the bare Pdn nanoclusters within the mesoporous pores of the support.
L‐cysteine‐protected Pdn nanoclusters supported on the reducible metal oxides CeO2, TiO2, and Fe3O4 exhibit a remarkable catalytic activity towards CO oxidation, significantly higher than that reported for Pd nanoparticle catalysts. Although the L‐cysteine ligands contain sulfur atoms, which could poison the Pd catalysts, a high catalytic activity of the ligand‐protected clusters, Pdn(L‐Cys)m, is observed on the three reducible oxides, where 100 % CO oxidation occurs at 93–110 °C.
Being a handle for synthesizing quaternary carbon centers and olefins, together with ubiquitous appearance in organic building blocks, makes tertiary alcohols valuable targets in synthesis. However, ...traditional syntheses of these alcohols have faced several challenges including the employment of functionalized reactive reagents, undesirable side reactions, and decomposition of the alcohol products under harsh conditions. The paucity of a synthetic approach to bulky tertiary alcohols prompts our interest to develop a benign catalytic protocol to tackle the current issues. Here, we have successfully demonstrated the use of ketyl radicals in intermolecular cross radical–radical coupling, which has opened a different door for accessing complex tertiary alcohols. On the other hand, by starting from feedstock and naturally derived chemicals without any pre-activation, it would be superior to traditional methodologies in the industrial context.
Basophils play an important role in orienting Th2 immune response, and in the pathogenesis of allergic and inflammatory disorders. However, the mechanism by which basophils are kept in check remains ...unclear and hence we explored the role of regulatory T cells (Treg cells) in this process. We demonstrate that human Treg cells do not suppress rather induce activation of basophils, and promote Th2 responses by IL-3 and STAT5-dependent mechanism.
Here we report a strategy for carbonyl addition with unactivated alkenes using an organic photocatalyst on both aldehyde and ketone substrates. This protocol grants us a good alternative to the ...traditional Barbier–Grignard allylation that exhibits poor functional group tolerance. With this method the stoichiometric use of metals can be avoided, high atom economy can be achieved and fewer by-products are generated.
A new rare earth based double perovskite oxide barium praseodymium cobalt niobate, BaPrCoNbO6 (BPCN) is synthesized by solid-state reaction technique. Rietveld analysis of X-ray diffraction (XRD) ...data shows that the compound crystallizes in a perovskite like tetragonal structure which belongs to the I4/mmm space group with lattice parameters a=b=5.6828(9)Å, c=8.063(2)Å. Structural analysis reveals 1:1 ordered arrangement for the Co2+ and Nb5+ cations over the six-coordinate B-sites of BPCN. The superlattice line (101) at 2θ=19.10° arising from the alternate ordering of Co2+ and Nb5+ sites is observed in the XRD pattern which confirms the presence of cation ordering in BPCN. Fourier transform infrared spectrum shows two phonon modes of the sample due to the antisymmetric NbO6 stretching vibration. The relaxation dynamics of the conductive process in BPCN is investigated in the temperature range 303 to 503K and in the frequency range 100Hz to 1MHz using impedance spectroscopy. The relaxation mechanism of the sample in the framework of electric modulus formalism is modeled by Davidson–Cole model (DCM). The values of α (distribution of relaxation time) for the DCM varies from 0.1 to 0.3 which suggests the asymmetric distribution of relaxation time for BPCN. The activation energy of the sample, calculated from both conductivity and modulus spectra, are found to be almost the same ~0.4eV, which indicates that the conduction mechanism for BPCN is polaron hopping. The scaling behaviour of the imaginary part of electric modulus suggests that the relaxation follows the same mechanism at various temperatures.
Rietveld refinement plot for BPCN. Inset shows the schematic presentation of the BPCN tetragonal unit cell. The Co2+ atoms are located at the centers of the CoO6 (blue) octahedra. The Nb5+ atoms are located at the centers of the NbO6 (green) octahedra. Display omitted
•BaPrCoNbO6 is synthesized for the first time.•Rietveld refinement of XRD data confirms tetragonal phase.•XRD confirms the presence of cation ordering in BaPrCoNbO6.•The activation energy is ~0.4eV.•The conduction mechanism for BPCN is due to polaron hopping.
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