Faint z ∼ 5 quasars with M1450 ∼ −23 mag are known to be potentially important contributors to the ultraviolet ionizing background in the postreionization era. However, their number density has not ...been well determined, making it difficult to assess their role in the early ionization of the intergalactic medium (IGM). In this work, we present the updated results of our z ∼ 5 quasar survey using the Infrared Medium-deep Survey (IMS), a near-infrared imaging survey covering an area of 85 deg2. From our spectroscopic observations with the Gemini Multi-Object Spectrograph on the Gemini-South 8 m telescope, we discovered eight new quasars at z ∼ 5 with −26.1 ≤ M1450 ≤ −23.3. Combining our IMS faint quasars (M1450 > −27 mag) with the brighter Sloan Digital Sky Survey quasars (M1450 < −27 mag), we derive the z ∼ 5 quasar luminosity function (QLF) without any fixed parameters down to the magnitude limit of M1450 = −23 mag. We find that the faint-end slope of the QLF is very flat ( ), with a characteristic luminosity of mag. The number density of z ∼ 5 quasars from the QLF gives an ionizing emissivity at 912 of 912 = (3.7-7.1) × 1023 erg s−1 Hz−1 Mpc−3 and an ionizing photon density of Mpc−3 s−1. These results imply that quasars are responsible for only 10%-20% (up to 50% even in the extreme case) of the photons required to completely ionize the IGM at z ∼ 5, disfavoring the idea that quasars alone could have ionized the IGM at z ∼ 5.
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•Pretreatment is guided for anaerobic digestion of agricultural biomass.•Characteristics of feedstock must be considered for optimizing pretreatment.•Alkali and steam explosion leads ...to an enhanced anaerobic digestion performance.•PEF, ionic liquids and rumen system can be future challenges for pretreatment.•Pretreatment is significant in a combined biorefinery with agricultural residue.
The anaerobic digestion (AD) of agricultural biomass is an attractive second generation biofuel with potential environmental and economic benefits. Most agricultural biomass contains lignocellulose which requires pretreatment prior to AD. For optimization, the pretreatment methods need to be specific to the characteristics of the biomass feedstock. In this review, cereal residue, fruit and vegetable wastes, grasses and animal manure were selected as the agricultural biomass candidates, and the fundamentals and current state of various pretreatment methods used for AD of these feedstocks were investigated. Several nonconventional methods (electrical, ionic liquid-based chemicals, ruminant biological pretreatment) offer potential as targeted pretreatments of lignocellulosic biomass, but each comes with its own challenges. Pursuing an energy-intensive route, a combined bioethanol-biogas production could be a promising a second biofuel refinery option, further emphasizing the importance of pretreatment when lignocellulosic feedstock is used.
As land application becomes one of the important waste utilization and disposal practices, soil is increasingly being seen as a major source of metal(loid)s reaching food chain, mainly through plant ...uptake and animal transfer. With greater public awareness of the implications of contaminated soils on human and animal health there has been increasing interest in developing technologies to remediate contaminated sites. Bioremediation is a natural process which relies on soil microorganisms and higher plants to alter metal(loid) bioavailability and can be enhanced by addition of organic amendments to soils. Large quantities of organic amendments, such as manure compost, biosolid and municipal solid wastes are used as a source of nutrients and also as a conditioner to improve the physical properties and fertility of soils. These organic amendments that are low in metal(loid)s can be used as a sink for reducing the bioavailability of metal(loid)s in contaminated soils and sediments through their effect on the adsorption, complexation, reduction and volatilization of metal(loid)s. This review examines the mechanisms for the enhanced bioremediation of metal(loid)s by organic amendments and discusses the practical implications in relation to sequestration and bioavailability of metal(loid)s in soils.
The surface plasmon effect on polymer solar cells and polymer light‐emitting diodes is demonstrated by using metal nanoparticles prepared from block copolymer templates. Light absorption of the ...polymer thin layer is increased with the incorporation of metallic nanostructures, resulting in a significant surface plasmon effect in the optoelectronic devices.
Accumulating data have indicated a fundamental role of eosinophils in regulating adipose tissue homeostasis. Here, we performed whole-genome RNA sequencing of the small intestinal tract, which ...suggested the presence of impaired lipid metabolism in eosinophil-deficient ΔdblGATA mice. ΔdblGATA mice fed a high-fat diet (HFD) showed reduced body fat mass, impaired enlargement of adipocytes, decreased expression of adipogenic genes, and developed glucose intolerance. HFD induced accumulation of eosinophils in the perigonadal white adipose tissue. Concordantly, adipocyte-differentiated 3T3-L1 cells promoted the migration of eosinophils through the expression of CCL11 (eotaxin-1) and likely promoted their survival through the expression of interleukin (IL)-3, IL-5, and granulocyte-macrophage colony-stimulating factor. HFD-fed ΔdblGATA mice showed increased infiltration of macrophages, CD4
T-cells, and B-cells, increased expression of interferon-γ, and decreased expression of IL-4 and IL-13 in white adipose tissue. Interferon-γ treatment significantly decreased lipid deposition in adipocyte-differentiated 3T3-L1 cells, while IL-4 treatment promoted lipid accumulation. Notably, HFD-fed ΔdblGATA mice showed increased lipid storage in the liver as compared with wild-type mice. We propose that obesity promotes the infiltration of eosinophils into adipose tissue that subsequently contribute to the metabolic homeostasis by promoting adipocyte maturation.
MicroRNA (miRNA) maturation is initiated by Microprocessor composed of RNase III DROSHA and its cofactor DGCR8, whose fidelity is critical for generation of functional miRNAs. To understand how ...Microprocessor recognizes pri-miRNAs, we here reconstitute human Microprocessor with purified recombinant proteins. We find that Microprocessor is an ∼364 kDa heterotrimeric complex of one DROSHA and two DGCR8 molecules. Together with a 23-amino acid peptide from DGCR8, DROSHA constitutes a minimal functional core. DROSHA serves as a “ruler” by measuring 11 bp from the basal ssRNA-dsRNA junction. DGCR8 interacts with the stem and apical elements through its dsRNA-binding domains and RNA-binding heme domain, respectively, allowing efficient and accurate processing. DROSHA and DGCR8, respectively, recognize the basal UG and apical UGU motifs, which ensure proper orientation of the complex. These findings clarify controversies over the action mechanism of DROSHA and allow us to build a general model for pri-miRNA processing.
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•Microprocessor is a trimeric complex with one DROSHA and two DGCR8•Functional core of Microprocessor contains DROSHA and the C-terminal tail of DGCR8•DROSHA serves as a ruler by recognizing the basal elements•DGCR8 interacts with the apical elements to ensure fidelity of processing
Functional reconstruction of human Microprocessor defines its molecular stoichiometry and the specific role of each component in substrate recognition and orientation, revealing a comprehensive processing mechanism of Microprocessor.
Stretchable organic light-emitting diodes are ubiquitous in the rapidly developing wearable display technology. However, low efficiency and poor mechanical stability inhibit their commercial ...applications owing to the restrictions generated by strain. Here, we demonstrate the exceptional performance of a transparent (molybdenum-trioxide/gold/molybdenum-trioxide) electrode for buckled, twistable, and geometrically stretchable organic light-emitting diodes under 2-dimensional random area strain with invariant color coordinates. The devices are fabricated on a thin optical-adhesive/elastomer with a small mechanical bending strain and water-proofed by optical-adhesive encapsulation in a sandwiched structure. The heat dissipation mechanism of the thin optical-adhesive substrate, thin elastomer-based devices or silicon dioxide nanoparticles reduces triplet-triplet annihilation, providing consistent performance at high exciton density, compared with thick elastomer and a glass substrate. The performance is enhanced by the nanoparticles in the optical-adhesive for light out-coupling and improved heat dissipation. A high current efficiency of ~82.4 cd/A and an external quantum efficiency of ~22.3% are achieved with minimum efficiency roll-off.A transparent twistable and stretchable MoO3/Au/MoO3 electrode is demonstrated by Choi et al. for organic light-emitting diodes. The device fabricated on thin elastomer shows enhanced EQE with minimum efficiency roll-off owing to the improved charge injection and heat dissipation from the substrate.
Ceramide is located at a key hub in the sphingolipid metabolic pathway and also acts as an important cellular signaling molecule. Ceramide contains one acyl chain which is attached to a sphingoid ...long chain base via an amide bond, with the acyl chain varying in length and degree of saturation. The identification of a family of six mammalian ceramide synthases (CerS) that synthesize ceramide with distinct acyl chains, has led to significant advances in our understanding of ceramide biology, including further delineation of the role of ceramide in various pathophysiologies in both mice and humans. Since ceramides, and the complex sphingolipids generated from ceramide, are implicated in disease, the CerS might potentially be novel targets for therapeutic intervention in the diseases in which the ceramide acyl chain length is altered. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
•Ceramide is generated by a family of six ceramide synthases (CerS).•Each CerS generates ceramides with defined acyl chain lengths.•CerS null mice show tissue-specific pathology.•Ceramide species with defined acyl chain lengths are involved in a number of diseases.•CerS might potentially be targets for therapeutic intervention.
The green fluorescent protein and its designed variants fluoresce efficiently. Because the isolated chromophore is not fluorescent in a practical sense, it is apparent that the protein environment ...plays a crucial role in its efficiency. Because of various obstacles in studying excited state dynamics of complex systems, however, the detailed mechanism of this efficiency enhancement is not yet clearly elucidated. Here, by adopting excited state nonadiabatic molecular dynamics simulations together with an interpolated quantum chemical potential model of the chromophore, we find that the strong electric field from the protein matrix contributes dominantly to the motional restriction of the chromophore. The delay in twisting motion subsequently obstructs the nonradiative decay that competes with fluorescence, leading naturally to an enhancement in light-emitting efficiency. Surprisingly, steric constraints make only a minor contribution to these aspects. Through residue specific analyses, we identify a group of key residues that control the excited state behavior. Testing a series of mutant GFPs with different brightnesses also supports the view regarding the importance of protein electrostatics. Our findings may provide a useful guide toward designing new fluorescent chemical systems in the future.
The concentrations, distributions, and bioaccumulation of nine organophosphate flame retardants (OPFRs) were investigated in both abiotic and biotic media, comprising river water, sediment, and ...crucian carp. The highest concentrations were observed in liver (6.22–18.1 ng/g ww), and the levels in muscle (4.23–7.75 ng/g ww) and gonad (3.08–7.70 ng/g ww) were similar. In whole blood, tris(2-butoxyethyl) phosphate (TBOEP; 31.1–256 ng/mL) accounted for 90% of the total OPFR concentration. Distributions of OPFRs differed between biotic and abiotic media, as tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), and TBOEP were dominant in abiotic media, whereas triethyl phosphate (TEP), tri-n-butyl phosphate (TNBP), TCEP, and TBOEP dominated in crucian carp. The TNBP had remarkable accumulation potential among nine OPFRs, which the TNBP concentrations in muscle increased with increased total length and body weight. The higher perfusion rate of TNBP to female eggs were observed rather than to male gonads as the concentrations were higher in males than in females, while the opposite results were observed in gonad. Moreover, the concentration of TNBP in female muscle began to decrease near maximum growth as a sexually dimorphic difference in crucian carp. This is the first study to simultaneously investigate the fate of OPFRs in biotic and abiotic media and to show sex differences.
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•The highest OPFR concentration was observed in liver, followed by muscle and gonad with similar levels.•The chlorinated OPFRs dominated in abiotic media, while the higher distribution of TEP and TNBP was observed in biotic media.•TNBP concentration in muscle increased as crucian carp grew but decreased after reaching near its maximum growth.•The sex different accumulation was observed for TNBP.
This is the first field-study to simultaneously investigate both biotic and abiotic environments, as well as sex difference related with the maternal transfer of OPFRs.
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