124 research outputs found
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 (CoĀ(OH)Ā(C<sub>6</sub>H<sub>5</sub>COO)Ā·H<sub>2</sub>O) 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 CoĀ(OH)Ā(C<sub>6</sub>H<sub>5</sub>COO)Ā·H<sub>2</sub>O nanobelts need significantly smaller overpotential (ā¼0.36
V) to reach 10 mAĀ·cm<sup>ā2</sup> of current density compared
with their CoĀ(OH)<sub>2</sub> (ā¼0.44 V) and Co<sub>3</sub>O<sub>4</sub> (ā¼0.387 V) counterparts, and even favorably compare
with most of the layered hydroxide-based electrocatalysts. Moreover,
the CoĀ(OH)Ā(C<sub>6</sub>H<sub>5</sub>COO)Ā·H<sub>2</sub>O nanobelts
retain a much higher stability than the RuO<sub>2</sub> 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 āfrom inorganic to organicā
strategy, that is, using tetrakisĀ(4-bromophenyl)Āmethane (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 4600ā6000 m<sup>2</sup>/g, 2.0ā7.9 g/cm<sup>3</sup>, and 10ā55 Ć
, 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 CO<sub>2</sub> capture, owing to its extremely high pore
volume and accessible surface area
Bioinspired CobaltāCitrate MetalāOrganic 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 cobaltācitrate metalāorganic
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
Co<sub>4</sub>O<sub>4</sub> 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<sup>ā2</sup> for OER catalysis, which is superior to that of most MOF-based electrocatalysts
and the standard Co<sub>3</sub>O<sub>4</sub> counterpart. The present
finding provides a better understanding of electroactive MOFs for
water oxidation
Tup1 depletion stabilizes the opaque state even at 37Ā°C.
<p>(<b>A)</b> Time course of Wor1 and Tup1 protein levels in opaque cells after shift from room temperature to 37Ā°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 37Ā°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 37Ā°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 37Ā°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 37Ā°C. Opaque <i>pMET3-TUP1</i> cells were grown in SCD with or without methionine at either room temperature or 37Ā°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 H<sub>2</sub>O, 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> 5ā 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
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
Non-glycolytic carbon sources alter Tup1 occupancy at the <i>WOR1</i> promoter and stabilize the opaque phase at 37Ā°C in <i>MTL</i>a/a and a/Ī± cells.
<p><b>(A)</b> Opaque stability of <i>MTL</i><b>a</b>/<b>a</b> cells cultured in various carbon sources at 37Ā°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 H<sub>2</sub>O and inoculated into fresh SC medium containing the indicated carbon sources. Cultures were grown at room temperature for 3hr then transferred to 37Ā°C for 24hr. Samples were plated onto SCD plates and grown for 5ā7 days to assess phase switching. <b>(B)</b> ChIP of Wor1 and Tup1 in opaque cells at room temperature and 37Ā°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 37Ā°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>/Ī±</i> cells cultured in liquid media at 37Ā°C for 24hr. Overnight cultures of opaque <i>MTL</i><b><i>a</i></b><i>/Ī±</i> cells carrying <i>pMAL2-WOR1</i> (HLY4543) from SCM were washed three times with H<sub>2</sub>O and inoculated into YNB medium containing the indicated carbon sources. Cultures were grown for 3hr at room temperature then shifted to 37Ā°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>/Ī±</i> cells on solid media. Overnight cultures of opaque <i>MTL</i><b><i>a</i></b><i>/Ī±</i> cells carrying <i>pMAL2-WOR1</i> (HLY4543) grown in SCM were washed three times with H<sub>2</sub>O then plated onto YNB plates containing 2% of the indicated carbon source. Plates were incubated at room temperature or 37Ā°C for 5ā7 days and scored for percent opaque. Both whole and sectored opaque colonies were counted as opaque.</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
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