The rapid growth of infant brains places an exceptionally high demand on the supply of nutrients from the diet, particularly for preterm infants. Sialic acid (Sia) is an essential component of brain ...gangliosides and the polysialic acid (polySia) chains that modify neural cell adhesion molecules (NCAM). Sia levels are high in human breast milk, predominately as N-acetylneuraminic acid (Neu5Ac). In contrast, infant formulas contain a low level of Sia consisting of both Neu5Ac and N-glycolylneuraminic acid (Neu5Gc). Neu5Gc is implicated in some human inflammatory diseases. Brain gangliosides and polysialylated NCAM play crucial roles in cell-to-cell interactions, neuronal outgrowth, modifying synaptic connectivity, and memory formation. In piglets, a diet rich in Sia increases the level of brain Sia and the expression of two learning-related genes and enhances learning and memory. The purpose of this review is to summarize the evidence showing the importance of dietary Sia as an essential nutrient for brain development and cognition.
The early stages of neurodevelopment in infants are crucial for establishing neural structures and synaptic connections that influence brain biochemistry well into adulthood. This postnatal period of ...rapid neural growth is of critical importance for cell migration, neurite outgrowth, synaptic plasticity, and axon fasciculation. These processes thus place an unusually high demand on the intracellular pool of nutrients and biochemical precursors. Sialic acid (Sia), a family of 9-carbon sugar acids, occurs in large amounts in human milk oligosaccharides and is an essential component of brain gangliosides and sialylated glycoproteins, particularly as precursors for the synthesis of the polysialic acid (polySia) glycan that post-translationally modify the cell membrane-associated neural cell adhesion molecules (NCAM). Human milk is noteworthy in containing exceptionally high levels of Sia-glycoconjugates. The predominate form of Sia in human milk is N-acetylneuraminic acid (Neu5Ac). Infant formula, however, contains low levels of Sia consisting of both Neu5Ac and N-glycolyneuraminic acid (Neu5Gc). Current studies implicate Neu5Gc in several human inflammatory diseases. Polysialylated NCAM and neural gangliosides both play critical roles in mediating cell-to-cell interactions important for neuronal outgrowth, synaptic connectivity, and memory formation. A diet rich in Sia also increases the level of Sia in the brains of postnatal piglets, the expression level of 2 learning-related genes, and enhances learning and memory.
Alternative splicing (AS) has been extensively studied in mammalian systems but much less in plants. Here we report AS events deduced from EST/cDNA analysis in two model plants: Arabidopsis and rice. ...In Arabidopsis, 4,707 (21.8%) of the genes with EST/cDNA evidence show 8,264 AS events. Approximately 56% of these events are intron retention (IntronR), and only 8% are exon skipping. In rice, 6,568 (21.2%) of the expressed genes display 14,542 AS events, of which 53.5% are IntronR and 13.8% are exon skipping. The consistent high frequency of IntronR suggests prevalence of splice site recognition by intron definition in plants. Different AS events within a given gene occur, for the most part, independently. In total, 36-43% of the AS events produce transcripts that would be targets of the non-sense-mediated decay pathway, if that pathway were to operate in plants as in humans. Forty percent of Arabidopsis AS genes are alternatively spliced also in rice, with some examples strongly suggesting a role of the AS event as an evolutionary conserved mechanism of posttranscriptional regulation. We created a comprehensive web-interfaced database to compile and visualize the evidence for alternative splicing in plants (Alternative Splicing in Plants, available at www.plantgdb.org/ASIP).
The COVID-19 pandemic is one of those global challenges that transcends territorial, political, ideological, religious, cultural, and certainly academic boundaries. Public health and healthcare ...workers are at the frontline, working to contain and to mitigate the spread of this disease. Although intervening biological and immunological responses against viral infection may seem far from the physical sciences and engineering that typically work with inanimate objects, there actually is much that canand shouldbe done to help in this global crisis. In this Perspective, we convert the basics of infectious respiratory diseases and viruses into physical sciences and engineering intuitions, and through this exercise, we present examples of questions, hypotheses, and research needs identified based on clinicians’ experiences. We hope researchers in the physical sciences and engineering will proactively study these challenges, develop new hypotheses, define new research areas, and work with biological researchers, healthcare, and public health professionals to create user-centered solutions and to inform the general public, so that we can better address the many challenges associated with the transmission and spread of infectious respiratory diseases.
The atroposelective synthesis of atropisomers with vicinal diaxes remains rare and challenging, due to the steric influence between the two axes and their unique topology. Herein, we disclose a ...single‐step construction of atropisomers with vicinal C−C and C−N chiral diaxes by cyclopentadiene (Cp)‐free cobalt‐catalyzed intramolecular atroposelective C−H annulation, providing the desired diaxial atropisomers of unique structures with decent stereocontrols of both axes (up to >99 % ee and 70 : 1 dr). The optically pure products bearing fluorophores show circular polarized luminescence (CPL) properties, being candidate materials for potential CPL applications. Atropisomerization experiments and density function theory (DFT) calculations are conducted to study the rotational barriers and rotation pathways of the diaxes.
A single‐step construction of atropisomers with vicinal C−C and C−N chiral diaxes by cyclopentadiene (Cp)‐free cobalt‐catalyzed intramolecular atroposelective C−H annulation with decent stereocontrols (up to >99 % ee and 70/1 dr) was reported. Atropisomerization experiments and DFT calculations are done to study the rotational barriers and pathways of the diaxes.
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•China’s air pollution mainly presents a spatial pattern of high-high agglomeration and low-low agglomeration.•New-type urbanization significantly reduces local air ...pollution.•Industrial structure, technological innovation and energy structure are important transmission mechanisms.•The impact of new-type urbanization on air pollution has regional heterogeneity.
To alleviate the ecological and environmental problems caused by rapid urban development, China has formulated and implemented the new-type urbanization strategy. However, there is insufficient empirical research on the specific relationship between new-type urbanization and air pollution. Therefore, based on the panel data of 30 provinces in China from 2005 to 2018, this paper constructs a comprehensive evaluation index system of new-type urbanization using the five dimensions of population, economy, space, society, and green. The spatial Durbin model and the spatial mediating model are used to discuss the spatial effect, transmission mechanism, and regional heterogeneity of new-type urbanization on air pollution. The results show that China’s air pollution mainly presents a spatial pattern of high-high agglomeration and low-low agglomeration, and there are spatial fluctuations. The construction of new-type urbanization significantly reduces local air pollution, and the industrial structure optimization, technological innovation, and energy structure adjustment are considered as important transmission mechanisms. However, under the fiscal decentralization and political tournament system in China, the policy implementation deviation may weaken the emission reduction effect of new-type urbanization, which is not conducive to regional environmental governance. From the sub-regional level, the impact of new-type urbanization on air pollution has regional heterogeneity. A robustness test confirms the reliability of our research conclusions. This study also proposes some policy suggestions that the government can utilize in grasping the policy focus of new-type urbanization construction to discover effective ways of controlling air pollution.
Reduction of calcium carbonate (CaCO3) scale formation on the equipment surface is essential in a wide variety of industrial fields. In this work, polydopamine/polytetrafluoroethylene (PDA/PTFE) ...coating prepared by the simple immersion on stainless steel (SS) surfaces was developed to suppress the CaCO3 scale adhesion. The PDA/PTFE‐coated surface showed the higher hydrophobicity (water contact angle = 133.50°) and lower surface free energy (11.92 mN/m) than the stainless‐steel surface. The scale inhibiting rate of the coated surface was up to 76.8% after 12‐hour immersion in the CaCO3 solution in comparison with the untreated SS. More bubbles were observed on the PDA/PTFE‐coated surfaces, and the number of bubbles increased with increasing solution temperature leading to less area for the scale adhesion. As a result, the PDA/PTFE coated surfaces have the higher antiscale ability at the higher solution temperature. Furthermore, the stripping and electrochemical corrosion tests demonstrated that the PDA/PTFE coating has the better stability and anticorrosion ability. The PDA/PTFE coating with the superior properties has potential application for the long‐lasting reduction of the scale formation.
The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However, their stability ...under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe‐metal–organic framework (NiFe‐MOFs) was conformally coated on oxygen‐vacancy‐rich BiVO4 (Ov‐BiVO4) as the protective layer and cocatalyst, forming a core–shell structure with caffeic acid as bridging agent. The as‐synthesized Ov‐BiVO4@NiFe‐MOFs exhibits enhanced stability and a remarkable photocurrent density of 5.3±0.15 mA cm−2 at 1.23 V (vs. RHE). The reduced coordination number of Ni(Fe)‐O and elevated valence state of Ni(Fe) in NiFe‐MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov‐BiVO4 to NiFe‐MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of a thin NiFe‐MOFs layer, leading to a photoanode of enhanced photocurrent and stability.
A core–shell Ov‐BiVO4@NiFe‐MOFs photoanode was constructed via a coordination‐assisted self‐assembly method. A NiFe‐MOFs thin layer acts as protective layer and cocatalyst to shift active sites from oxygen vacancies to NiFe‐MOFs, leading to improved stability and activity for OER. This molecular‐based approach tailors the coordination and electronic structure of active sites and provides mechanistic insights for rational design of photocatalysts.
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•g-C3N4/SnS2/SnO2 nanocomposites were firstly fabricated by solvothermal method after 30 min ultrasonic irradiation.•Reaction rate constant of Cr(VI) can be improved 41.7- and ...4.0-time, compared with pure g-C3N4 and SnS2/SnO2, respectively.•More than 90% lost photocatalytic activity can be regenerated by water-washing.
A kind of g-C3N4/SnS2/SnO2 nanocomposite was firstly prepared by solvothermal method at 140 °C for 4 h after 30 min ultrasonic irradiation. X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), transmission electron microscopy (TEM) and electrical/optical testing techniques confirmed that the oxygen atoms in SnO2 might be doped in the g-C3N4 in the synthesizing process, resulting to a good combination of SnS2/SnO2 nanosheets and g-C3N4 nanoparticles by SnOC bond, which would have an influence on the light adsorption, carriers transfer, and electron-hole separation efficiency of g-C3N4/SnS2/SnO2. Additionally, the ultrasonic assisted solvothermal reaction could also promote the formation of oxygen vacancies on the surface of the material, which leads to the up-shift of valence band. The photocatalytic properties of the g-C3N4/SnS2/SnO2 were studied by the reduction of aqueous Cr(VI). The data clearly indicated that the photocatalytic activity of as-synthesized composites depends on their compositions, and reaction rate constant of Cr(VI) on the composite-C (with the mass ratio of 1:3) with visible light (λ > 420 nm) driven can be improved 41.7- and 4.0-time compared with pure g-C3N4 and SnS2/SnO2, respectively. Additionally, more than 90% lost photocatalytic activity of composite-C can be regenerated by water-washing and drying treatment. The present study provided an efficient method for removing toxic Cr(VI) ions via photoreduction utilizing visible light irradiation (λ > 420 nm).
To support an ever-increasing population, modern agriculture faces numerous challenges that pose major threats to global food and energy security. Plant-associated microbes, with their many plant ...growth-promoting (PGP) traits, have enormous potential in helping to solve these challenges. However, the results of their use in agriculture have been variable, probably because of poor colonization. Phytomicrobiome engineering is an emerging field of synthetic biology that may offer ways to alleviate this limitation. This review highlights recent advances in both bottom-up and top-down approaches to engineering non-model bacteria and microbiomes to promote beneficial plant–microbe interactions, as well as advances in strategies to evaluate these interactions. Biosafety, biosecurity, and biocontainment strategies to address the environmental concerns associated with field use of synthetic microbes are also discussed.
Mutualistic microbes associated with plants have enormous potential for economical and sustainable agriculture.There are two approaches to plant microbiome engineering: the bottom-up approach that involves isolating, engineering, and reintroducing specific microbes, and the top-down approach that involves synthetic ecology, using horizontal gene transfer to a broad range of hosts in situ and then phenotyping the microbiome.Recent advances in genome engineering tools, meta-omic tools, computational tools, and genome-wide functional genomics can improve our ability to engineer microbes for biocontrol, biofertilization, and biostimulation, as well as enhanced crop productivity and yield.Various devices can facilitate the evaluation of genetically modified microbes before field studies.Robust biosafety, biosecurity, and biocontainment strategies need to be developed for use of genetically modified microbes in the environment.
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