Effect of Mechanical Stretching on DNA Conductance

Studying the structural and charge transport properties in DNA is important for unraveling molecular scale processes and developing device applications of DNA molecules. Here we study the effect of mechanical stretching-induced structural changes on charge transport in single DNA molecules. The charge transport follows the hopping mechanism for DNA molecules with lengths varying from 6 to 26 base pairs, but the conductance is highly sensitive to mechanical stretching, showing an abrupt decrease at surprisingly short stretching distances and weak dependence on DNA length. We attribute this force-induced conductance decrease to the breaking of hydrogen bonds in the base pairs at the end of the sequence and describe the data with a mechanical model

Effect of the MFE on the Fasting Blood Glucose (FBG) and Glucosylated Serum Protein (GSP) of STZ-induced Diabetic Mice.^a

a<p>Values are the mean ± SD; n = 8. ^b p<0.05 versus the control group. ^c p<0.01 versus the control group.</p

Chemical structure of compounds 1−24 isolated from mulberry fruit (<i>Morus alba</i> L.)

<p>Chemical structure of compounds 1−24 isolated from mulberry fruit (<i>Morus alba</i> L.)</p

HPLC-PDA chromatogram of mulberry fruit (<i>Morus alba</i> L.) polyphenol enhanced extract.

<p>HPLC-PDA chromatogram of mulberry fruit (<i>Morus alba</i> L.) polyphenol enhanced extract.</p

α-Glucosidase Inhibitory Activities of the Isolated Compounds 1−25.^a

a<p>Values are the mean ± SD; n = 3. ^b Compounds <b>17</b>−<b>25</b> did not show α-glucosidase inhibitory activity (IC50 >1000 <i>μ</i>M).</p

Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) of the Extracts from Mulberry Fruit.^a

a<p>Values are the mean ± SD; n = 3. GAE, gallic acid equivalent. RE, rutin equivalent; NA, no assay.</p

DPPH Radical-scavenging and Superoxide anion Radical-scavenging Activities of The Isolated Compounds 1–25.^a

a<p>Values are the mean ± SD; n = 3.</p>b<p>Compounds <b>17</b>, <b>19</b>, <b>22</b> and <b>23</b> did not show DPPH radical-scavenging or superoxide anion radical-scavenging activity (EC50 >500 <i>μ</i>M).</p

Tuning the Electromechanical Properties of Single DNA Molecular Junctions

Understanding the interplay between the electrical and mechanical properties of DNA molecules is important for the design and characterization of molecular electronic devices, as well as understanding the role of charge transport in biological functions. However, to date, force-induced melting has limited our ability to investigate the response of DNA molecular conductance to stretching. Here we present a new molecule–electrode linker based on a hairpin-like design, which prevents force-induced melting at the end of single DNA molecules during stretching by stretching both strands of the duplex evenly. We find that the new linker group gives larger conductance than previously measured DNA–electrode linkers, which attach to the end of one strand of the duplex. In addition to changing the conductance the new linker also stabilizes the molecule during stretching, increasing the length a single DNA molecule can be stretched before an abrupt decrease in conductance. Fitting these electromechanical properties to a spring model, we show that distortion is more evenly distributed across the single DNA molecule during stretching, and thus the electromechanical effects of the π–π coupling between neighboring bases is measured

DPPH Radical-scavenging, Superoxide anion Radical-scavenging Activities and α-glucosidase Inhibitory Activity of the Extracts from Mulberry Fruit.^{a, b}

a<p>Values are the mean ± SD; n = 3. ^b DPPH used in the DPPH radical-scavenging assay of the extracts was 2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl (Sigma-Aldrich). NA, no assay.</p