Context. Compton-thick active galactic nuclei (CT-AGNs), defined by a column density of NH >= 1.5 & times; 1024 cm-2, are so heavily absorbed that their X-ray emission is often feeble and can even be undetectable by X-ray instruments in some cases. Nevertheless, their radiation is expected to be a substantial contributor to the cosmic X-ray background (CXB), predicting that CT-AGNs would comprise at least similar to 30% of the total AGN population. Aims. Cosmological Evolution Survey (COSMOS) reported that the identified CT-AGN fraction falls far below theoretical expectations, indicating that a substantial population of CT-AGNs is hidden due to their low photon counts or due to their flux lying below the current flux limits of X-ray instruments. This work focuses on identifying CT-AGNs hidden among mid-infrared (MIR) selected AGNs. Methods. First, we selected a sample of 1,104 MIR-selected AGNs that were covered, but individually undetected by X-ray. Next, we reduced the X-ray data in the COSMOS and analyzed multiwavelength data in our sample to derive the key physical parameters required for the CT-AGN identification. Results. Using MIR diagnostics, we found 7 to 23 CT-AGN candidates. Their subsequent X-ray stacking analysis revealed a clear detection at > 3 sigma significance in the soft band and only a > 1 sigma significance in the hard band. We fit the stacked soft- and hard-band fluxes with a physical model and confirm that these sources are absorbed by Compton-thick material. However, CT-AGNs ultimately constituted only 2.1% (23/1104) of our sample, significantly below the fraction predicted by CXB synthesis models. This indicates that a considerable population of CT-AGNs remains missed by our selection. A comparison of host-galaxy properties between CT-AGNs and non-CT-AGNs reveals no significant differences.
This study highlights the diversity and ecological importance of freshwater endophytic fungi in Ratnapura district, Sabaragamuwa Province, Sri Lanka. Freshwater plant samples were collected from Chandrika tank (Embilipitiya), a seasonal pond at Haughton Estate (Kalawana), and Thiniyamita stream (Wewelkandura). Six endophytic species were isolated associated with different freshwater plants. These endophytes comprised of four Colletotrichum species C. hydei sp. nov. (RUFCC24116) and C. chlorophyti (RUFCC24117) from Vallisneria americana; C. chlorophyti (RUFCC241117) and C. vittalense (RUFCC241112) from Nymphaea pubescens; C. truncatum (RUFCC241119) from Lagenandra ovata); Daldinia eschscholtzii (RUFCC24114) from Hydrilla verticillata; and Nigrospora lacticolonia (RUFCC24115) from Persicaria glabra. Multi-locus phylogenetic analyses were used for species delimitation, based on ITS, GAPDH, ACT, CHS-1, and tub2 gene regions for Colletotrichum species; ITS, LSU, and rpb2 for Daldinia eschscholtzii; and ITS and tef1-alpha for Nigrospora lacticolonia. These results provide important insights into fungal host range and biodiversity at the global level.
During a field survey conducted in the mountainous regions of Shigu Village, Lijiang, Yunnan Province, China, two fungal specimens resembling Inosperma were collected. Morphological comparisons coupled with phylogenetic analyses based on the internal transcribed spacer (ITS) and the nuclear ribosomal large subunit (LSU) regions revealed that the specimen represents a novel species of Inosperma, herein described as I. lijiangense. This species is distinguished by a light reddish white to reddish brown, dry, fibrillose pileus; adnate to slightly sinuate, milk white to grayish orange lamellae; and a solid, cylindrical stipe that is slightly swollen at the base and lacks both an annulus and odor. The basidiospores are ellipsoid to ovoid, smooth, and pale yellowish brown. Phylogenetic analysis indicates that the new species, I. lijiangense, represented by specimens GMB-W1237 (holotype) and GMB-W1238 (paratype), constitutes a distinct lineage within Inosperma. A comprehensive description, accompanying illustrations, and results of the phylogenetic analysis are provided.
Metal–organic frameworks (MOFs) emerge as promising materials for catalyzing the oxygen evolution reaction (OER), a fundamental process in water splitting. This study describes the development of an optimized CoFe-based MOF, demonstrating significant enhancement in its catalytic activity for the OER. The catalytic activity of zeolitic imidazolate framework-67 (ZIF-67) is markedly improved via a facile post-synthetic modification. This process involved partially substituting cobalt ions at specific sites via metal-ion exchange/etching under mild reaction conditions. A remarkable 100 mV reduction in the overpotential is observed at 10 mA cm−2 with ZIF-67/Fe-1 compared with pristine ZIF-67, reaching only 287 mV. Incorporating Fe into Co‐based MOFs improves the efficiency of reaction kinetics and charge transfer, resulting in optimal OER activity. This enhancement is attributed to the synergistic effect between Fe and Co within the MOFs. A combination of experimental characterization and theoretical simulation demonstrated the modulation of the electronic structure of Co sites and intermediate binding affinity. The developed synthetic strategy exhibits broad applicability, enabling the facile synthesis of other MOFs, such as ZIF-67/Cu-1, ZIF-67/Mn-1, and ZIF-67/Ni-1, for efficient OER catalysis. The proposed strategy can be easily extended to other MOF-based OER electrocatalysts.
In this study, we report a new taxon, Calocybe barangensis, from Barang, Bajaur District, Khyber Pakhtunkhwa, Pakistan. The species was described as new to science using molecular phylogenetic analysis of combined ITS and LSU datasets, as well as comparisons of its macro- and micromorphological characteristics with those of similar taxa. The new species forms a separate clade in the phylogenetic tree and differs in having small basidiomata with dark yellowish-brown spores and large, globose to subglobose basidiospores (5.9-7.2 & times; 4.7-5.6 mu m). A full description, illustrations, and phylogenetic analysis results of the new species are provided.
