Interlayer Expansion of Layered Cobalt Hydroxide Nanobelts to Highly Improve Oxygen Evolution Electrocatalysis

The water oxidation reaction is known to be energy-inefficient and generally considered as a major bottleneck for water splitting. Exploring electrocatalysts with high-efficiency and at low cost is vital to widespread utilization of this technology, but is still a big challenge. Here we report an effective strategy based on an expanding interlayer of layered structures to realize a great enhancement of the catalytic performance of the oxygen evolution reaction from water splitting. Well-defined nanobelts of layer-structured cobalt benzoate hydroxide (Co­(OH)­(C₆H₅COO)·H₂O) are successfully prepared in terms of a simple hydrothermal process. Intercalation with benzoate ions induces the interlayer expansion of the cobalt hydroxide, which is useful for the accommodation of more electrolyte ions and favorable for their diffusion and transport. The as-prepared Co­(OH)­(C₆H₅COO)·H₂O nanobelts need significantly smaller overpotential (∼0.36 V) to reach 10 mA·cm^–2 of current density compared with their Co­(OH)₂ (∼0.44 V) and Co₃O₄ (∼0.387 V) counterparts, and even favorably compare with most of the layered hydroxide-based electrocatalysts. Moreover, the Co­(OH)­(C₆H₅COO)·H₂O nanobelts retain a much higher stability than the RuO₂ reference in alkaline solution. This approach would be utilized to design and develop high-performance layered hydroxide-based electrocatalysts

From Inorganic to Organic Strategy To Design Porous Aromatic Frameworks for High-Capacity Gas Storage

Developing high-capacity gas storage materials is still an important issue, because it is closely related to carbon dioxide capture and hydrogen storage. This work proposes a “from inorganic to organic” strategy, that is, using tetrakis­(4-bromophenyl)­methane (TBM) to replace silicon in zeolites, to design porous aromatic frameworks (PAF_XXXs) with extremely high pore volume and accessible surface area, because the silicon atom in the silicon-based zeolites and the TBM ligand have the same coordination manner. Through the adoption of this strategy, 115 organic PAF_XXXs based on the inorganic zeolite structures were designed. These designed PAF_XXXs have the same topology with the corresponding matrix zeolites but possess significantly higher porosity than matrix zeolites. In general, the surface area, pore volume, and pore size of PAF_XXX are in the ranges of 4600–6000 m²/g, 2.0–7.9 g/cm³, and 10–55 Å, respectively. In particular, the hydrogen uptake of PAF_RWY reaches 5.9 wt % at 100 bar and 298 K, exceeding the DOE 2015 target (5.5 wt %) for hydrogen storage. Moreover, PAF_RWY is also a promising candidate for methane storage and CO₂ capture, owing to its extremely high pore volume and accessible surface area

Bioinspired Cobalt–Citrate Metal–Organic Framework as an Efficient Electrocatalyst for Water Oxidation

Efficient and cost-effective oxygen evolution reaction (OER) electrocatalysts are closely associated with many important energy conversion technologies. Herein, we first report an oxygen-evolving cobalt–citrate metal–organic framework (MOF, UTSA-16) for highly efficient electrocatalytic water oxidation. Benefiting from synergistic cooperation of intrinsic open porous structure, in situ formed high valent cobalt species, and existing Co₄O₄ cubane, the UTSA-16 exhibits excellent activity toward OER catalysis in alkaline medium. The UTSA-16 needs only 408 mV to offer a current density of 10 mA cm^–2 for OER catalysis, which is superior to that of most MOF-based electrocatalysts and the standard Co₃O₄ counterpart. The present finding provides a better understanding of electroactive MOFs for water oxidation

Tup1 depletion stabilizes the opaque state even at 37°C.

<p>(<b>A)</b> Time course of Wor1 and Tup1 protein levels in opaque cells after shift from room temperature to 37°C. Overnight cultures of opaque cells of a strain carrying both Wor1-FLAG and Tup1-HA (HLY4541) were inoculated, grown to mid-log phase, then shifted to 37°C and grown for the indicated times. Protein level was assessed by Western blot as described. <b>(B)</b> ChIP of Wor1-FLAG and Tup1-HA at the <i>WOR1</i> promoter in opaque cells shifted to room temperature or 37°C. Overnight cultures of opaque cells of a strain carrying both Wor1-FLAG and Tup1-HA (HLY4541) and an untagged control strain (JYC1) were diluted in SCD and grown to log phase at room temperature. Cultures were divided and incubated at either room temperature or 37°C for one hour, formaldehyde cross-linked, and harvested for ChIP. Enrichment is presented as a ratio of the -4kb region of the <i>WOR1</i> promoter IP (bound/input) over an <i>ADE2</i> control region IP (bound/input) of the tagged strain, further normalized to the control strain. Values are the average of three independent ChIP experiments with error bars representing the s.d. <b>(C)</b> Tup1 depletion in opaque cells at room temperature and 37°C. Opaque <i>pMET3-TUP1</i> cells were grown in SCD with or without methionine at either room temperature or 37°C for 24hr. Expression levels of the indicated genes were measured by qPCR and normalized to <i>ACT1</i>. Average expression level of three independent qPCR experiments are plotted with error bars representing the s.d. Samples were also taken at the indicated times, washed three times with H₂O, and plated onto SCD Met- plates to assess phase switching.</p

Tup1 depletion bypasses the requirement for Wor1 in the expression of <i>WOR1</i> and key opaque regulators.

<p><b>(A)</b> Expression levels in the conditional Tup1 mutant and <i>wor1 pMET3-tup1</i> conditional double mutant haploid strains. <i>pMET3-TUP1</i> (HLY4533) and <i>pMET3-TUP1 wor1</i> (HLY4539) were grown at room temperature for 48hr in the presence or absence of methionine. <b>(B)</b> Expression levels in diploid <i>wor1</i> and <i>wor1 tup1</i> mutant strains. Overnight cultures of <i>MTL</i><b><i>a</i></b><i>/</i><b><i>a</i></b> <i>wor1</i> (HLY3570), <i>wor1 tup1</i> (HLY4540), and a control strain (JYC1) were inoculated into fresh SCD and grown to log phase. Expression levels of the indicated genes in <b>(A)</b> and <b>(B)</b> were measured by qPCR and normalized to <i>ACT1</i>. <i>WOR1</i> expression was measured by qPCR using primers specific to either the <i>WOR1</i> 5’ UTR or the <i>WOR1</i> coding region (CDS). Average expression level of three independent qPCR experiments was plotted with error bars representing the s.d.<b>(C)</b> Genetic model of Wor1-Tup1 regulation of <i>WOR1</i> expression.</p

Tup1 binds along the <i>WOR1</i> promoter differentially in white and opaque phases.

<p><b>(A)</b> ChIP of Tup1-HA in white and opaque cells. Overnight cultures of white and opaque cells of a wild-type strain (JYC5) and a strain carrying Tup1-HA (HLY4538) were diluted in SCD and grown to log phase at room temperature before formaldehyde. Enrichment is presented as a ratio of qPCR of the <i>WOR1</i> promoter IP (bound/input) over an <i>ADE2</i> control region IP (bound/input) of the tagged strain, further normalized to the control strain. Values are the average of three independent ChIP experiments with error bars representing the s.d. <b>(B)</b> Additional qPCR of Tup1 binding around -2.4kb upstream of the <i>WOR1</i> TSS in white cells from <b>(A)</b>.</p

Non-glycolytic carbon sources alter Tup1 occupancy at the <i>WOR1</i> promoter and stabilize the opaque phase at 37°C in <i>MTL</i>a/a and a/α cells.

<p><b>(A)</b> Opaque stability of <i>MTL</i><b>a</b>/<b>a</b> cells cultured in various carbon sources at 37°C for 24hr. Overnight cultures of <i>MTL</i><b>a</b>/<b>a</b> WT opaque cells (HLY3555) grown in SCD were washed three times with H₂O and inoculated into fresh SC medium containing the indicated carbon sources. Cultures were grown at room temperature for 3hr then transferred to 37°C for 24hr. Samples were plated onto SCD plates and grown for 5–7 days to assess phase switching. <b>(B)</b> ChIP of Wor1 and Tup1 in opaque cells at room temperature and 37°C in different carbon sources. Opaque cells carrying both Wor1-FLAG and Tup1-HA (HLY4541) and an untagged strain (JYC1) were grown in SC medium containing the indicated carbon source overnight at room temperature. Cultures were diluted and grown to log phase, then grown at either room temperature or 37°C for 1hr for ChIP. Enrichment is presented as a ratio of the -4kb region of the <i>WOR1</i> promoter IP (bound/input) over an <i>ADE2</i> control region IP (bound/input) of the tagged strain, further normalized to the control strain. Values are the average of three independent ChIP experiments with error bars representing the s.d. (<b>C)</b> Opaque stability of <i>MTL</i><b><i>a</i></b><i>/α</i> cells cultured in liquid media at 37°C for 24hr. Overnight cultures of opaque <i>MTL</i><b><i>a</i></b><i>/α</i> cells carrying <i>pMAL2-WOR1</i> (HLY4543) from SCM were washed three times with H₂O and inoculated into YNB medium containing the indicated carbon sources. Cultures were grown for 3hr at room temperature then shifted to 37°C. Cells were collected after 24hr and gene expression levels were analyzed by qPCR and normalized to <i>ACT1</i>. Average expression level of three independent qPCR experiments are plotted with error bars representing the s.d. <b>(D)</b> Opaque stability of <i>MTL</i><b><i>a</i></b><i>/α</i> cells on solid media. Overnight cultures of opaque <i>MTL</i><b><i>a</i></b><i>/α</i> cells carrying <i>pMAL2-WOR1</i> (HLY4543) grown in SCM were washed three times with H₂O then plated onto YNB plates containing 2% of the indicated carbon source. Plates were incubated at room temperature or 37°C for 5–7 days and scored for percent opaque. Both whole and sectored opaque colonies were counted as opaque.</p

Comparison with three methods on five real-world networks by cover rate and uncovered nodes.

*<p>the bold data marked with an asterisk (*) is the best value of each evaluation on the dataset for three methods.</p>**<p>CR: Cover Rate; UN: number of Uncovered Nodes.</p

The sensibility analysis of included studies for serum ferritin.

<p>The sensibility analysis of included studies for serum ferritin.</p

Iron Status in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis - Fig 5

<p>Funnel plot for publication bias test between-group meta-analysis (A) on serum ferritin levels (B) on serum iron levels.</p