Core-Packing-Related Vibrational Properties of Thiol-Protected Gold Nanoclusters and Their Excited-State Behavior

Thiolate-protected gold nanoclusters, with unique nuclearity- and structure-dependent properties, have been extensively used in energy conversion and catalysis; however, the mystery between kernel structures and properties remains to be revealed. Here, the influence of core packing on the electronic structure, vibrational properties, and excited-state dynamics of four gold nanoclusters with various kernel structures is explored using density functional theory combined with time-domain nonadiabatic molecular dynamics simulations. We elucidate the correlation between the geometrical structure and excited-state dynamics of gold nanoclusters. The distinct carrier lifetimes of the four nanoclusters are attributed to various electron–phonon couplings arising from the different vibrational properties caused by core packing. We have identified specific phonon modes that participate in the electron–hole recombination dynamics, which are related to the gold core of nanoclusters. This study paints a physical picture from the geometric configuration, electronic structure, vibrational properties, and carrier lifetime of these nanoclusters, thereby facilitating their potential application in optoelectronic materials

Core-Packing-Related Vibrational Properties of Thiol-Protected Gold Nanoclusters and Their Excited-State Behavior

Thiolate-protected gold nanoclusters, with unique nuclearity- and structure-dependent properties, have been extensively used in energy conversion and catalysis; however, the mystery between kernel structures and properties remains to be revealed. Here, the influence of core packing on the electronic structure, vibrational properties, and excited-state dynamics of four gold nanoclusters with various kernel structures is explored using density functional theory combined with time-domain nonadiabatic molecular dynamics simulations. We elucidate the correlation between the geometrical structure and excited-state dynamics of gold nanoclusters. The distinct carrier lifetimes of the four nanoclusters are attributed to various electron–phonon couplings arising from the different vibrational properties caused by core packing. We have identified specific phonon modes that participate in the electron–hole recombination dynamics, which are related to the gold core of nanoclusters. This study paints a physical picture from the geometric configuration, electronic structure, vibrational properties, and carrier lifetime of these nanoclusters, thereby facilitating their potential application in optoelectronic materials

Whole-Transcriptome Selection and Evaluation of Internal Reference Genes for Expression Analysis in Protocorm Development of <i>Dendrobium officinale</i> Kimura <i>et</i> Migo

<div><p><i>Dendrobium officinale</i> Kimu <i>et</i> Migo has increased many researchers’ interest for its high medical and horticultural values and the molecular mechanism of its protocorm development remains unclear. In this study, 19 genes from 26 most stably expressed genes in whole transcriptome of protocorms and 5 housekeeping genes were used as candidate reference genes and screened with 4 application softwares (geNorm, NormFinder, BestKeeper and RefFinder). The results showed that a few reference genes could effectively normalize expression level of specific genes in protocorm development and the optimal top 2 reference genes were <i>ASS</i> and <i>APH1L</i>. Meanwhile, validation of <i>GNOM</i>, <i>AP2</i> and temperature induced gene (<i>TIL</i>) for normalization demonstrates the usefulness of the validated candidate reference genes. The expression profiles of these genes varied under protocorms and temperature stress according to the stablest and unstablest reference genes, which proved the importance of the choice of appropriate reference genes. The first systematic evaluation of stably expressed genes will be very useful in the future analysis of specific genes expression in <i>D</i>. <i>officinale</i>.</p></div

Rank of 19 CIRGs calculated by NormFinder and BestKeeper.

<p>Rank of 19 CIRGs calculated by NormFinder and BestKeeper.</p

Relative quantification of <i>GNOM</i>, <i>AP2</i> and <i>TIL</i> expression using validated reference genes for normalization in protocorm and temperature stress.

<p>(A, B) <i>ASS</i> was the stablest gene, <i>ASS</i>+<i>APH1L</i> was the best combination reference genes. <i>TXNL2</i> was the unstablest gene. (C) <i>T2-17479</i>+<i>PhLP3</i> was the best combination reference genes; <i>T2-17479</i>, <i>PhLP3</i>, <i>GABAT3</i>, <i>TFIIB</i> and <i>ASS</i> were the optimal 5 stablest IRGs; <i>T2-17479</i>, <i>PhLP3</i>, <i>GABAT3</i>, <i>TFIIB</i>, <i>ASS</i> and <i>Actin1</i> were the 6 stablest IRGs. All these IRGs above were calculated by geNorm.</p

Primer sequences and amplicon characteristics of 31 tested genes and 2 <i>Actin</i> genes of <i>D</i>.<i>officinale</i>.

<p>Primer sequences and amplicon characteristics of 31 tested genes and 2 <i>Actin</i> genes of <i>D</i>.<i>officinale</i>.</p

Comprehensive ranking of CIRGs in all samples, according to their expression stability values as given by RefFinder based on geNorm, NormFinder, BestKeeper, and comparative delta-Ct methods.

<p>A~F represents protocorms, tissues, both of protocorms and tissues, stem parts, temperature stress and PEG stress respectively.</p

Rank of the more stable 10 CIRGs by NormFinder and BestKeeper.

<p>Rank of the more stable 10 CIRGs by NormFinder and BestKeeper.</p

Validation of expression stability of housekeeping genes.

<p>Validation of expression stability of housekeeping genes.</p

Patient demographics.

<p>Patient demographics.</p