19 research outputs found
Characterisation of an atmospheric-pressure air DBD discharge
Combining the advantages of non-equilibrium plasmas with the ease of atmospheric-pressure operation, dielectric barrier discharges (DBD) are widely used in many fields and applications, including ozone production, sterilization, tumour treatments and surface modification
Revised manuscript marked by red from An elliptical liquid inclusion in an infinite elastic plane
Revised manuscript marked by re
Surface [4 + 2] Cycloaddition Reaction of Thymine on Si(111)7×7 Observed by Scanning Tunneling Microscopy
The
early stage of thymine (Thy) adsorption on Si(111)Â7×7
surface is studied with scanning tunneling microscopy (STM) and density
functional theory (DFT)-based computational method. Bright protrusions
corresponding to the adsorbed thymine molecules are observed in both
empty-state and filled-state STM images. These bright protrusions
in the empty-state images exhibit three different degrees [lower (L),
medium (M), and higher (H)] of intensities. The L and M protrusions
are found on the adatom–restatom pairs in the 7 × 7 unit
cell, indicating bidentate configurations for Thy adsorption. A free
Thy molecule has been found to interact with the Si surface by a two-step
process: Thy first undergoes keto–enol tautomerization to form
the more stable dienol tautomer, which then binds to the Si adatom–restatom
pair via the [4 + 2] cycloaddition reaction, leading to two different
adproducts. Our DFT/B3LYP/6-31++GÂ(d,p) calculations show three plausible
cycloaddition products, with the 1,4-cyclohexadiene adproduct being
more stable than 3,6- and 2,5-cyclohexadienes. Our calculations also
suggest the viability of formation of a Thy molecule hydrogen-bonded
with the bidentate Thy adproducts already on the surface. Statistical
analysis for three different exposures of Thy on the 7 × 7 surface
reveals that the L protrusion has the highest relative surface concentration
(80%), with the M (16%) and H features (4%) being significantly less
popular. These results lead us to attribute the L and M protrusions
to the 1,4- and the 3,6-cycloaddition products, respectively, with
the least popular H protrusion assigned to a Thy molecule hydrogen-bonded
to the bidentate Thy, all attached to an adatom–restatom pair.
The observation of [4 + 2] cycloaddition products on the Si surface
confirms the formation of precursor dienol Thy tautomer. This surface-mediated
two-step reaction pathway for Thy is unique for surfaces, in contrast
to keto–enol tautomerization that is mainly observed in the
solution phase either by acid- or base-catalyzed pathways. Our STM
study coupled with our separate XPS work have demonstrated that this
type of tautomerization can also be observed on Si surfaces, and this
can initiate the subsequent cycloaddition reactions of Thy molecule
with the surface
Interfacial Inversion, Interference, and IR Absorption in Vibrational Sum Frequency Scattering Experiments
Molecular interfacial structure greatly determines the
properties
of nano- and microscale systems. Vibrational sum frequency scattering
(SFS) spectroscopy is a unique interface-selective tool to measure
the interfacial vibrational spectrum of sub-micron to micron-scale
objects dispersed in liquid and solid media. The interfacial structure
is extracted from the interfacial susceptibility, a physical property
derived from the intensity. Here, we describe the effect of infrared
absorption that occurs in a bulk medium that is spectroscopically
complex and use the results to investigate the effects of interfacial
inversion, interfacial interference, and interfacial interference
combined with absorption. We use the same three chemicals to do so,
hexadecane oil, water, and a neutral Span80 surfactant. For all cases,
the effective surface susceptibility can be retrieved from the intensity.
We further find that inverting the phases results in different interfacial
structures, even though they are composed of the same three chemicals,
and explain this in terms of the different interactions that are necessary
to stabilize the drops: steric stabilization for water drops in oil
vs. charge stabilization for oil drops in water. Interfacial interference
can be used to estimate the surface density of different compounds
matlab code from An elliptical liquid inclusion in an infinite elastic plane
code to get the numerical result
Comparison of the structure and properties of equiatomic and non-equiatomic multicomponent alloys
<p>A series of equiatomic and non-equiatomic Fe<i>x</i>(NiCrCo)<sub>100−<i>x</i></sub> (at.-%, <i>x</i> = 25, 45, 55, 65, 75 and 85) multicomponent alloys were prepared and studied. With the increase in <i>x</i>, the phase structure of the alloys evolves from a single FCC phase (<i>x</i> = 25, 45 and 55), to a mixture of FCC and BCC phases (<i>x</i> = 55) and finally to a single BCC phase (<i>x</i> = 65 and 75). As a result, the BCC-structured alloys have much higher strength and hardness than the FCC-structured alloys. The existing VEC criteria are unable to predict the FCC-BCC phase transition in these alloys.</p
Silencing of augmenter of liver regeneration inhibited cell proliferation and triggered apoptosis in U266 human multiple myeloma cells
<div><p>Augmenter of liver regeneration (ALR) is a thermostable cytokine that was originally identified to promote the growth of hepatocytes. This study was conducted to explore the expression and function of ALR in multiple myeloma (MM), a common hematologic malignancy. Real-time PCR and western blot analysis were performed to detect the expression of ALR in U266 human MM cells and healthy peripheral blood mononuclear cells (PBMCs). U266 MM cells were exposed to 20 or 40 μg/mL of recombinant ALR and tested for cell proliferation. Small interfering RNA-mediated silencing of ALR was done to investigate the role of ALR in cell proliferation, apoptosis, and cytokine production. Compared to PBMCs, U266 MM cells exhibited significantly higher levels of ALR at both the mRNA and protein levels. The addition of recombinant ALR protein significantly promoted the proliferation of U266 cells. In contrast, knockdown of ALR led to a significant decline in the viability and proliferation of U266 cells. Annexin-V/PI staining analysis demonstrated that ALR downregulation increased apoptosis in U266 MM cells, compared to control cells (20.1±1.1 vs 9.1±0.3%, P<0.05). Moreover, ALR depletion reduced the Bcl-2 mRNA level by 40% and raised the Bax mRNA level by 2-fold. Additionally, conditioned medium from ALR-depleted U266 cells had significantly lower concentrations of interleukin-6 than control cells (P<0.05). Taken together, ALR contributed to the proliferation and survival of U266 MM cells, and targeting ALR may have therapeutic potential in the treatment of MM.</p></div
Role and Evolution of Nanoparticle Structure and Chemical State during the Oxidation of NO over Size- and Shape-Controlled Pt/γ-Al<sub>2</sub>O<sub>3</sub> Catalysts under Operando Conditions
The structure and chemical state
of size-selected Pt nanoparticles
(NPs) supported on γ-Al<sub>2</sub>O<sub>3</sub> were studied
during the oxidation of NO using X-ray absorption near-edge spectroscopy
and extended X-ray absorption fine-structure spectroscopy measurements
under operando conditions. The data revealed the formation of PtO<sub><i>x</i></sub> species in the course of the reaction that
remained present at the maximum temperature studied, 350 °C.
The PtO<sub><i>x</i></sub> species were found in all samples,
but those with the smallest NPs showed the highest degree of oxidation.
Moreover, NO-induced nanoparticle redispersion was observed at temperatures
below 150 °C for all catalysts studied. Catalytic tests showed
activity toward the oxidation of NO for all samples. Nevertheless,
the catalyst with the smallest NPs was found to be the least active,
which is explained by a more extensive formation of PtO<sub><i>x</i></sub> species in this catalyst and their detrimental contribution
to the oxidation of NO
Probing polarization response of monolayer cell cultures with photon entanglement
This study addresses the critical need for high signal-to-noise ratio in optical detection methods for biological sample discrimination under low-photon-flux conditions to ensure accuracy without compromising sample integrity. We explore polarization-based probing, which often excels over intensity modulation when assessing a specimen's morphology. Leveraging non-classical light sources, our approach capitalizes on sub-Poissonian photon statistics and quantum correlation-based measurements. We present a novel, highly sensitive method for probing single-layer cell cultures using entangled photon pairs. Our approach demonstrates capability in monolayer cell analysis, distinguishing between two types of monolayer cells and their host medium. The experimental results highlight our method's sensitivity, showcasing its potential for biological sample detection using quantum techniques, and paving the way for advanced diagnostic methodologies
Rankl expression predicts poor prognosis in gastric cancer patients: results from a retrospective and single-center analysis
<div><p>The receptor activator of nuclear factor κB ligand (RANKL)/RANK pathway plays an important role in the prognosis of several solid tumor types, but its role in gastric cancer prognosis has been poorly characterized. A total of 116 gastric cancer patients who underwent surgical resection were enrolled in this study. Expressions of RANKL and RANK in gastric cancer tissues were detected using immunohistochemical staining. Thirty-eight patients (33%) showed a high level of RANKL expression and 61 patients (53%) showed a high level of RANK expression. There was a positive correlation between expressions of RANKL and RANK (P=0.014, r=0.221). A high level of RANKL expression indicated shorter overall survival (OS) (P=0.008), and was associated with a higher pathological tumor/lymph node/metastasis (pTNM) stage (P=0.035), while no significant correlation was detected between RANK expression and clinicopathological parameters. RANKL also predicted poor prognosis in patients with high RANK expression (P=0.008) and Bormann's type III/IV (P=0.002). Furthermore, RANKL expression correlated with pTNM stage according to high RANK expression (P=0.009), while no significance was found in patients with low RANK expression (P=1.000). Together, our results revealed that high expression of RANKL could predict worse outcomes in gastric cancer especially combined with RANK detection, and thereby this pathway could be a useful prognostic indicator of gastric cancer.</p></div